diff --git a/docs/swagger/traPortfolio.v1.yaml b/docs/swagger/traPortfolio.v1.yaml
index e035e318..a66cebdc 100644
--- a/docs/swagger/traPortfolio.v1.yaml
+++ b/docs/swagger/traPortfolio.v1.yaml
@@ -1121,7 +1121,7 @@ components:
               type: array
               description: コンテストチーム
               items:
-                $ref: "#/components/schemas/ContestTeam"
+                $ref: "#/components/schemas/ContestTeamWithoutMembers"
           required:
             - teams
     ContestDetail:
@@ -1148,10 +1148,10 @@ components:
             - link
             - description
             - teams
-    ContestTeam:
-      title: ContestTeam
+    ContestTeamWithoutMembers:
+      title: ContestTeamWithoutMembers
       type: object
-      description: コンテストチーム情報
+      description: コンテストチーム情報(チームメンバーなし)
       properties:
         id:
           type: string
@@ -1168,6 +1168,21 @@ components:
         - id
         - name
         - result
+    ContestTeam:
+      title: ContestTeam
+      type: object
+      description: コンテストチーム情報
+      allOf:
+        - $ref: "#/components/schemas/ContestTeamWithoutMembers"
+        - type: object
+          properties:
+            members:
+              type: array
+              description: チームメンバーのユーザー情報
+              items:
+                $ref: '#/components/schemas/User'
+          required:
+            - members
     ContestTeamDetail:
       title: ContestTeamDetail
       type: object
@@ -1191,7 +1206,6 @@ components:
           required:
             - link
             - description
-            - members
     PrPermitted:
       title: PrPermitted
       type: boolean
diff --git a/domain/contest.go b/domain/contest.go
index 8d84c79f..00d017ca 100644
--- a/domain/contest.go
+++ b/domain/contest.go
@@ -20,16 +20,20 @@ type ContestDetail struct {
 	ContestTeams []*ContestTeam
 }
 
-type ContestTeam struct {
+type ContestTeamWithoutMembers struct {
 	ID        uuid.UUID
 	ContestID uuid.UUID
 	Name      string
 	Result    string
 }
 
+type ContestTeam struct {
+	ContestTeamWithoutMembers
+	Members []*User
+}
+
 type ContestTeamDetail struct {
 	ContestTeam
 	Link        string
 	Description string
-	Members     []*User
 }
diff --git a/domain/user.go b/domain/user.go
index d4e5f229..a3c6361a 100644
--- a/domain/user.go
+++ b/domain/user.go
@@ -66,7 +66,7 @@ type UserContest struct {
 	Name      string    // コンテスト名
 	TimeStart time.Time
 	TimeEnd   time.Time
-	Teams     []*ContestTeam // ユーザーが所属するチームのリスト
+	Teams     []*ContestTeamWithoutMembers // ユーザーが所属するチームのリスト
 }
 
 type UserGroup struct {
diff --git a/integration_tests/repository/user_test.go b/integration_tests/repository/user_test.go
index 7f43bb61..744a5f2b 100644
--- a/integration_tests/repository/user_test.go
+++ b/integration_tests/repository/user_test.go
@@ -545,14 +545,16 @@ func TestUserRepository_GetContests(t *testing.T) {
 	mustAddContestTeamMembers(t, contestRepo, team2.ID, []uuid.UUID{user1.ID})
 
 	expected1 := []*domain.UserContest{
-		newUserContest(t, &contest1.Contest, []*domain.ContestTeam{&team1.ContestTeam}),
-		newUserContest(t, &contest2.Contest, []*domain.ContestTeam{&team2.ContestTeam}),
+		newUserContest(t, &contest1.Contest, []*domain.ContestTeamWithoutMembers{&team1.ContestTeam.ContestTeamWithoutMembers}),
+		newUserContest(t, &contest2.Contest, []*domain.ContestTeamWithoutMembers{&team2.ContestTeam.ContestTeamWithoutMembers}),
 	}
 	contests1, err := userRepo.GetContests(context.Background(), user1.ID)
 	assert.NoError(t, err)
 	assert.ElementsMatch(t, expected1, contests1)
 
-	expected2 := []*domain.UserContest{newUserContest(t, &contest1.Contest, []*domain.ContestTeam{&team1.ContestTeam})}
+	expected2 := []*domain.UserContest{
+		newUserContest(t, &contest1.Contest, []*domain.ContestTeamWithoutMembers{&team1.ContestTeam.ContestTeamWithoutMembers}),
+	}
 	contests2, err := userRepo.GetContests(context.Background(), user2.ID)
 	assert.NoError(t, err)
 	assert.ElementsMatch(t, expected2, contests2)
@@ -580,8 +582,7 @@ func newUserProject(t *testing.T, args *urepository.CreateProjectMemberArgs, pro
 	}
 }
 
-func newUserContest(t *testing.T, contest *domain.Contest, teams []*domain.ContestTeam) *domain.UserContest {
-	t.Helper()
+func newUserContest(t *testing.T, contest *domain.Contest, teams []*domain.ContestTeamWithoutMembers) *domain.UserContest {
 	return &domain.UserContest{
 		ID:        contest.ID,
 		Name:      contest.Name,
diff --git a/interfaces/handler/contest.go b/interfaces/handler/contest.go
index c2c8fb07..73f400a1 100644
--- a/interfaces/handler/contest.go
+++ b/interfaces/handler/contest.go
@@ -55,7 +55,11 @@ func (h *ContestHandler) GetContest(c echo.Context) error {
 
 	teams := make([]schema.ContestTeam, len(contest.ContestTeams))
 	for i, v := range contest.ContestTeams {
-		teams[i] = newContestTeam(v.ID, v.Name, v.Result)
+		members := make([]schema.User, len(v.Members))
+		for j, ct := range v.Members {
+			members[j] = newUser(ct.ID, ct.Name, ct.RealName())
+		}
+		teams[i] = newContestTeam(v.ID, v.Name, v.Result, members)
 	}
 
 	res := newContestDetail(
@@ -89,11 +93,7 @@ func (h *ContestHandler) CreateContest(c echo.Context) error {
 		return err
 	}
 
-	contestTeams := make([]schema.ContestTeam, 0, len(contest.ContestTeams))
-	for _, team := range contest.ContestTeams {
-		contestTeams = append(contestTeams, newContestTeam(team.ID, team.Name, team.Result))
-	}
-	res := newContestDetail(newContest(contest.ID, contest.Name, contest.TimeStart, contest.TimeEnd), contest.Link, contest.Description, contestTeams)
+	res := newContestDetail(newContest(contest.ID, contest.Name, contest.TimeStart, contest.TimeEnd), contest.Link, contest.Description, []schema.ContestTeam{})
 
 	return c.JSON(http.StatusCreated, res)
 }
@@ -159,7 +159,11 @@ func (h *ContestHandler) GetContestTeams(c echo.Context) error {
 
 	res := make([]schema.ContestTeam, len(contestTeams))
 	for i, v := range contestTeams {
-		res[i] = newContestTeam(v.ID, v.Name, v.Result)
+		members := make([]schema.User, len(v.Members))
+		for j, ct := range v.Members {
+			members[j] = newUser(ct.ID, ct.Name, ct.RealName())
+		}
+		res[i] = newContestTeam(v.ID, v.Name, v.Result, members)
 	}
 
 	return c.JSON(http.StatusOK, res)
@@ -189,10 +193,9 @@ func (h *ContestHandler) GetContestTeam(c echo.Context) error {
 	}
 
 	res := newContestTeamDetail(
-		newContestTeam(contestTeam.ID, contestTeam.Name, contestTeam.Result),
+		newContestTeam(contestTeam.ID, contestTeam.Name, contestTeam.Result, members),
 		contestTeam.Link,
 		contestTeam.Description,
-		members,
 	)
 
 	return c.JSON(http.StatusOK, res)
@@ -223,7 +226,7 @@ func (h *ContestHandler) AddContestTeam(c echo.Context) error {
 		return err
 	}
 
-	res := newContestTeam(contestTeam.ID, contestTeam.Name, contestTeam.Result)
+	res := newContestTeam(contestTeam.ID, contestTeam.Name, contestTeam.Result, []schema.User{})
 
 	return c.JSON(http.StatusCreated, res)
 }
@@ -384,20 +387,29 @@ func newContestDetail(contest schema.Contest, link string, description string, t
 	}
 }
 
-func newContestTeam(id uuid.UUID, name string, result string) schema.ContestTeam {
+func newContestTeam(id uuid.UUID, name string, result string, members []schema.User) schema.ContestTeam {
 	return schema.ContestTeam{
+		Id:      id,
+		Name:    name,
+		Result:  result,
+		Members: members,
+	}
+}
+
+func newContestTeamWithoutMembers(id uuid.UUID, name string, result string) schema.ContestTeamWithoutMembers {
+	return schema.ContestTeamWithoutMembers{
 		Id:     id,
 		Name:   name,
 		Result: result,
 	}
 }
 
-func newContestTeamDetail(team schema.ContestTeam, link string, description string, members []schema.User) schema.ContestTeamDetail {
+func newContestTeamDetail(team schema.ContestTeam, link string, description string) schema.ContestTeamDetail {
 	return schema.ContestTeamDetail{
 		Description: description,
 		Id:          team.Id,
 		Link:        link,
-		Members:     members,
+		Members:     team.Members,
 		Name:        team.Name,
 		Result:      team.Result,
 	}
diff --git a/interfaces/handler/contest_test.go b/interfaces/handler/contest_test.go
index 3f778dc6..f7016368 100644
--- a/interfaces/handler/contest_test.go
+++ b/interfaces/handler/contest_test.go
@@ -124,26 +124,47 @@ func makeContest(t *testing.T) (*domain.ContestDetail, *schema.ContestDetail) {
 		Description: random.AlphaNumeric(),
 		ContestTeams: []*domain.ContestTeam{
 			{
-				ID:        getContestID[1],
-				ContestID: getContestID[0],
-				Name:      random.AlphaNumeric(),
-				Result:    random.AlphaNumeric(),
+				ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+					ID:        getContestID[1],
+					ContestID: getContestID[0],
+					Name:      random.AlphaNumeric(),
+					Result:    random.AlphaNumeric(),
+				},
+				Members: []*domain.User{
+					domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), random.Bool()),
+					domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), random.Bool()),
+				},
 			},
 			{
-				ID:        getContestID[2],
-				ContestID: getContestID[0],
-				Name:      random.AlphaNumeric(),
-				Result:    random.AlphaNumeric(),
+				ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+					ID:        getContestID[2],
+					ContestID: getContestID[0],
+					Name:      random.AlphaNumeric(),
+					Result:    random.AlphaNumeric(),
+				},
+				Members: []*domain.User{
+					domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), random.Bool()),
+					domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), random.Bool()),
+				},
 			},
 		},
 	}
 
 	teams := make([]schema.ContestTeam, len(d.ContestTeams))
 	for i, v := range d.ContestTeams {
+		member := make([]schema.User, len(v.Members))
+		for j, w := range v.Members {
+			member[j] = schema.User{
+				Id:       w.ID,
+				Name:     w.Name,
+				RealName: w.RealName(),
+			}
+		}
 		teams[i] = schema.ContestTeam{
-			Id:     v.ID,
-			Name:   v.Name,
-			Result: v.Result,
+			Id:      v.ID,
+			Members: member,
+			Name:    v.Name,
+			Result:  v.Result,
 		}
 	}
 
@@ -511,26 +532,46 @@ func TestContestHandler_GetContestTeams(t *testing.T) {
 				contestID := random.UUID()
 				repoContestTeams := []*domain.ContestTeam{
 					{
-						ID:        random.UUID(),
-						ContestID: contestID,
-						Name:      random.AlphaNumeric(),
-						Result:    random.AlphaNumeric(),
+						ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+							ID:        random.UUID(),
+							ContestID: contestID,
+							Name:      random.AlphaNumeric(),
+							Result:    random.AlphaNumeric(),
+						},
+						Members: []*domain.User{
+							domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), random.Bool()),
+							domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), random.Bool()),
+						},
 					},
 					{
-						ID:        random.UUID(),
-						ContestID: contestID,
-						Name:      random.AlphaNumeric(),
-						Result:    random.AlphaNumeric(),
+						ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+							ID:        random.UUID(),
+							ContestID: contestID,
+							Name:      random.AlphaNumeric(),
+							Result:    random.AlphaNumeric(),
+						},
+						Members: []*domain.User{
+							domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), random.Bool()),
+							domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), random.Bool()),
+						},
 					},
 				}
 				hres = []*schema.ContestTeam{
 					{
-						Id:     repoContestTeams[0].ID,
+						Id: repoContestTeams[0].ID,
+						Members: []schema.User{
+							{Id: repoContestTeams[0].Members[0].ID, Name: repoContestTeams[0].Members[0].Name, RealName: repoContestTeams[0].Members[0].RealName()},
+							{Id: repoContestTeams[0].Members[1].ID, Name: repoContestTeams[0].Members[1].Name, RealName: repoContestTeams[0].Members[1].RealName()},
+						},
 						Name:   repoContestTeams[0].Name,
 						Result: repoContestTeams[0].Result,
 					},
 					{
-						Id:     repoContestTeams[1].ID,
+						Id: repoContestTeams[1].ID,
+						Members: []schema.User{
+							{Id: repoContestTeams[1].Members[0].ID, Name: repoContestTeams[1].Members[0].Name, RealName: repoContestTeams[1].Members[0].RealName()},
+							{Id: repoContestTeams[1].Members[1].ID, Name: repoContestTeams[1].Members[1].Name, RealName: repoContestTeams[1].Members[1].RealName()},
+						},
 						Name:   repoContestTeams[1].Name,
 						Result: repoContestTeams[1].Result,
 					},
@@ -580,17 +621,19 @@ func TestContestHandler_GetContestTeam(t *testing.T) {
 				contestID := random.UUID()
 				repoContestTeamDetail := domain.ContestTeamDetail{
 					ContestTeam: domain.ContestTeam{
-						ID:        teamID,
-						ContestID: contestID,
-						Name:      random.AlphaNumeric(),
-						Result:    random.AlphaNumeric(),
+						ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+							ID:        teamID,
+							ContestID: contestID,
+							Name:      random.AlphaNumeric(),
+							Result:    random.AlphaNumeric(),
+						},
+						Members: []*domain.User{
+							domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), random.Bool()),
+							domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), random.Bool()),
+						},
 					},
 					Link:        random.AlphaNumeric(),
 					Description: random.AlphaNumeric(),
-					Members: []*domain.User{
-						domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), random.Bool()),
-						domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), random.Bool()),
-					},
 				}
 				members := make([]schema.User, 0, len(repoContestTeamDetail.Members))
 				for _, member := range repoContestTeamDetail.Members {
@@ -684,19 +727,22 @@ func TestContestHandler_AddContestTeam(t *testing.T) {
 				}
 				want := domain.ContestTeamDetail{
 					ContestTeam: domain.ContestTeam{
-						ID:        teamID,
-						ContestID: contestID,
-						Name:      args.Name,
-						Result:    args.Result.ValueOrZero(),
+						ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+							ID:        teamID,
+							ContestID: contestID,
+							Name:      args.Name,
+							Result:    args.Result.ValueOrZero(),
+						},
+						Members: make([]*domain.User, 0),
 					},
 					Link:        args.Link.ValueOrZero(),
 					Description: args.Description,
-					Members:     nil,
 				}
 				expectedResBody := schema.ContestTeam{
-					Id:     teamID,
-					Name:   want.Name,
-					Result: want.Result,
+					Id:      teamID,
+					Members: make([]schema.User, 0),
+					Name:    want.Name,
+					Result:  want.Result,
 				}
 				s.EXPECT().CreateContestTeam(anyCtx{}, contestID, &args).Return(&want, nil)
 				return reqBody, expectedResBody, fmt.Sprintf("/api/v1/contests/%s/teams", contestID)
diff --git a/interfaces/handler/schema/schema_gen.go b/interfaces/handler/schema/schema_gen.go
index 7c233350..df0ab85b 100644
--- a/interfaces/handler/schema/schema_gen.go
+++ b/interfaces/handler/schema/schema_gen.go
@@ -111,11 +111,14 @@ type ContestDetail struct {
 	Teams []ContestTeam `json:"teams"`
 }
 
-// ContestTeam コンテストチーム情報
+// ContestTeam defines model for ContestTeam.
 type ContestTeam struct {
 	// Id コンテストチームuuid
 	Id uuid.UUID `json:"id"`
 
+	// Members チームメンバーのユーザー情報
+	Members []User `json:"members"`
+
 	// Name チーム名
 	Name string `json:"name"`
 
@@ -144,6 +147,18 @@ type ContestTeamDetail struct {
 	Result string `json:"result"`
 }
 
+// ContestTeamWithoutMembers コンテストチーム情報(チームメンバーなし)
+type ContestTeamWithoutMembers struct {
+	// Id コンテストチームuuid
+	Id uuid.UUID `json:"id"`
+
+	// Name チーム名
+	Name string `json:"name"`
+
+	// Result 順位などの結果
+	Result string `json:"result"`
+}
+
 // CreateContestRequest 新規コンテストリクエスト
 type CreateContestRequest struct {
 	// Description コンテスト説明
@@ -466,7 +481,7 @@ type UserContest struct {
 	Name string `json:"name"`
 
 	// Teams コンテストチーム
-	Teams []ContestTeam `json:"teams"`
+	Teams []ContestTeamWithoutMembers `json:"teams"`
 }
 
 // UserDetail defines model for UserDetail.
diff --git a/interfaces/handler/user.go b/interfaces/handler/user.go
index 6c544453..2d560349 100644
--- a/interfaces/handler/user.go
+++ b/interfaces/handler/user.go
@@ -262,9 +262,9 @@ func (h *UserHandler) GetUserContests(c echo.Context) error {
 
 	res := make([]schema.UserContest, len(contests))
 	for i, c := range contests {
-		teams := make([]schema.ContestTeam, len(c.Teams))
+		teams := make([]schema.ContestTeamWithoutMembers, len(c.Teams))
 		for j, ct := range c.Teams {
-			teams[j] = newContestTeam(ct.ID, ct.Name, ct.Result)
+			teams[j] = newContestTeamWithoutMembers(ct.ID, ct.Name, ct.Result)
 		}
 		res[i] = newUserContest(
 			newContest(c.ID, c.Name, c.TimeStart, c.TimeEnd),
@@ -357,7 +357,7 @@ func newUserProject(id uuid.UUID, name string, duration schema.YearWithSemesterD
 	}
 }
 
-func newUserContest(contest schema.Contest, teams []schema.ContestTeam) schema.UserContest {
+func newUserContest(contest schema.Contest, teams []schema.ContestTeamWithoutMembers) schema.UserContest {
 	return schema.UserContest{
 		Id:       contest.Id,
 		Name:     contest.Name,
diff --git a/interfaces/handler/user_test.go b/interfaces/handler/user_test.go
index 9770ab43..20004095 100644
--- a/interfaces/handler/user_test.go
+++ b/interfaces/handler/user_test.go
@@ -1189,7 +1189,7 @@ func TestUserHandler_GetUserContests(t *testing.T) {
 				Name:      random.AlphaNumeric(),
 				TimeStart: random.Time(),
 				TimeEnd:   random.Time(),
-				Teams: []*domain.ContestTeam{
+				Teams: []*domain.ContestTeamWithoutMembers{
 					{
 						ID:        random.UUID(),
 						ContestID: random.UUID(),
@@ -1201,8 +1201,8 @@ func TestUserHandler_GetUserContests(t *testing.T) {
 
 			hcontest := newUserContest(
 				newContest(rcontest.ID, rcontest.Name, rcontest.TimeStart, rcontest.TimeEnd),
-				[]schema.ContestTeam{
-					newContestTeam(rcontest.Teams[0].ID, rcontest.Teams[0].Name, rcontest.Teams[0].Result),
+				[]schema.ContestTeamWithoutMembers{
+					newContestTeamWithoutMembers(rcontest.Teams[0].ID, rcontest.Teams[0].Name, rcontest.Teams[0].Result),
 				},
 			)
 
diff --git a/interfaces/repository/contest_impl.go b/interfaces/repository/contest_impl.go
index c5b10c1e..a9f0162a 100644
--- a/interfaces/repository/contest_impl.go
+++ b/interfaces/repository/contest_impl.go
@@ -178,6 +178,7 @@ func (r *ContestRepository) DeleteContest(ctx context.Context, contestID uuid.UU
 }
 
 func (r *ContestRepository) GetContestTeams(ctx context.Context, contestID uuid.UUID) ([]*domain.ContestTeam, error) {
+	//IDがcontestIDであるようなcontestが存在するかチェック
 	if err := r.h.
 		WithContext(ctx).
 		Where(&model.Contest{ID: contestID}).
@@ -186,6 +187,7 @@ func (r *ContestRepository) GetContestTeams(ctx context.Context, contestID uuid.
 		return nil, err
 	}
 
+	//ContestIDがcontestIDであるようなcontestTeamを10件まで列挙する
 	teams := make([]*model.ContestTeam, 10)
 	err := r.h.
 		WithContext(ctx).
@@ -195,15 +197,58 @@ func (r *ContestRepository) GetContestTeams(ctx context.Context, contestID uuid.
 	if err != nil {
 		return nil, err
 	}
+
+	//teamsの要素vについてTeamIDがv.IDである(TeamIDがteamsIDListに入っているID)ようなContestTeamUserBelongingを列挙する
+	var teamsIDList = make([]uuid.UUID, len(teams))
+	for i, v := range teams {
+		teamsIDList[i] = v.ID
+	}
+
+	var belongings = []*model.ContestTeamUserBelonging{}
+	err = r.h.
+		WithContext(ctx).
+		Preload("User").
+		Where("team_id IN (?)", teamsIDList).
+		Find(&belongings).
+		Error()
+
+	if err != nil {
+		return nil, err
+	}
+
+	belongingMap := make(map[uuid.UUID]([]*model.ContestTeamUserBelonging))
+	for _, v := range belongings {
+		belongingMap[v.TeamID] = append(belongingMap[v.TeamID], v)
+	}
+
+	nameMap, err := r.makeUserNameMap()
+	if err != nil {
+		return nil, err
+	}
+
 	result := make([]*domain.ContestTeam, 0, len(teams))
 	for _, v := range teams {
+		members := make([]*domain.User, len(belongingMap[v.ID]))
+		for i, w := range belongingMap[v.ID] {
+			u := w.User
+			members[i] = domain.NewUser(u.ID, u.Name, nameMap[u.Name], u.Check)
+		}
+
 		result = append(result, &domain.ContestTeam{
-			ID:        v.ID,
-			ContestID: v.ContestID,
-			Name:      v.Name,
-			Result:    v.Result,
+			ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+				ID:        v.ID,
+				ContestID: v.ContestID,
+				Name:      v.Name,
+				Result:    v.Result,
+			},
+			Members: members,
 		})
 	}
+
+	// if len(result) == 0 {
+	// 	result = []*domain.ContestTeam{}
+	// }
+
 	return result, nil
 }
 
@@ -218,16 +263,40 @@ func (r *ContestRepository) GetContestTeam(ctx context.Context, contestID uuid.U
 		return nil, err
 	}
 
+	var belongings []*model.ContestTeamUserBelonging
+	err := r.h.
+		WithContext(ctx).
+		Preload("User").
+		Where(&model.ContestTeamUserBelonging{TeamID: teamID}).
+		Find(&belongings).
+		Error()
+	if err != nil {
+		return nil, err
+	}
+
+	nameMap, err := r.makeUserNameMap()
+	if err != nil {
+		return nil, err
+	}
+
+	members := make([]*domain.User, len(belongings))
+	for i, w := range belongings {
+		u := w.User
+		members[i] = domain.NewUser(u.ID, u.Name, nameMap[u.Name], u.Check)
+	}
+
 	res := &domain.ContestTeamDetail{
 		ContestTeam: domain.ContestTeam{
-			ID:        team.ID,
-			ContestID: team.ContestID,
-			Name:      team.Name,
-			Result:    team.Result,
+			ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+				ID:        team.ID,
+				ContestID: team.ContestID,
+				Name:      team.Name,
+				Result:    team.Result,
+			},
+			Members: members,
 		},
 		Link:        team.Link,
 		Description: team.Description,
-		// Members:
 	}
 	return res, nil
 }
@@ -257,14 +326,16 @@ func (r *ContestRepository) CreateContestTeam(ctx context.Context, contestID uui
 
 	result := &domain.ContestTeamDetail{
 		ContestTeam: domain.ContestTeam{
-			ID:        contestTeam.ID,
-			ContestID: contestTeam.ContestID,
-			Name:      contestTeam.Name,
-			Result:    contestTeam.Result,
+			ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+				ID:        contestTeam.ID,
+				ContestID: contestTeam.ContestID,
+				Name:      contestTeam.Name,
+				Result:    contestTeam.Result,
+			},
+			Members: make([]*domain.User, 0),
 		},
 		Link:        contestTeam.Link,
 		Description: contestTeam.Description,
-		Members:     nil,
 	}
 	return result, nil
 }
diff --git a/interfaces/repository/contest_impl_test.go b/interfaces/repository/contest_impl_test.go
index 2d1d4667..b9b339e4 100644
--- a/interfaces/repository/contest_impl_test.go
+++ b/interfaces/repository/contest_impl_test.go
@@ -540,10 +540,16 @@ func TestContestRepository_GetContestTeams(t *testing.T) {
 			},
 			want: []*domain.ContestTeam{
 				{
-					ID:        random.UUID(),
-					ContestID: cid,
-					Name:      random.AlphaNumeric(),
-					Result:    random.AlphaNumeric(),
+					ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+						ID:        random.UUID(),
+						ContestID: cid,
+						Name:      random.AlphaNumeric(),
+						Result:    random.AlphaNumeric(),
+					},
+					Members: []*domain.User{
+						domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), true),
+						domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), true),
+					},
 				},
 			},
 			setup: func(f mockContestRepositoryFields, args args, want []*domain.ContestTeam) {
@@ -559,6 +565,33 @@ func TestContestRepository_GetContestTeams(t *testing.T) {
 					ExpectQuery(makeSQLQueryRegexp("SELECT * FROM `contest_teams` WHERE `contest_teams`.`contest_id` = ?")).
 					WithArgs(args.contestID).
 					WillReturnRows(rows)
+
+				teamsIDList := make([]driver.Value, len(want))
+				teamRows := sqlmock.NewRows([]string{"team_id", "user_id"})
+				for i, u := range want {
+					teamsIDList[i] = u.ID
+					for _, w := range u.Members {
+						teamRows.AddRow(u.ID, w.ID)
+					}
+				}
+
+				f.h.Mock.
+					ExpectQuery(makeSQLQueryRegexp("SELECT * FROM `contest_team_user_belongings` WHERE team_id IN (?)")).
+					WithArgs(teamsIDList...).
+					WillReturnRows(teamRows)
+
+				userIDs := make([]driver.Value, len(want[0].Members))
+				userRows := sqlmock.NewRows([]string{"id", "name", "check"})
+				for i, u := range want[0].Members {
+					userIDs[i] = u.ID
+					userRows.AddRow(u.ID, u.Name, u.Check)
+				}
+				f.h.Mock.
+					ExpectQuery(makeSQLQueryRegexp("SELECT * FROM `users` WHERE `users`.`id` IN (?,?)")).
+					WithArgs(userIDs...).
+					WillReturnRows(userRows)
+
+				f.portal.EXPECT().GetUsers().Return(makePortalUsers(t, want[0].Members), nil)
 			},
 			assertion: assert.NoError,
 		},
@@ -636,16 +669,22 @@ func TestContestRepository_GetContestTeam(t *testing.T) {
 			},
 			want: &domain.ContestTeamDetail{
 				ContestTeam: domain.ContestTeam{
-					ID:        tid,
-					ContestID: cid,
-					Name:      random.AlphaNumeric(),
-					Result:    random.AlphaNumeric(),
+					ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+						ID:        tid,
+						ContestID: cid,
+						Name:      random.AlphaNumeric(),
+						Result:    random.AlphaNumeric(),
+					},
+					Members: []*domain.User{
+						domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), true),
+						domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), true),
+					},
 				},
 				Link:        random.RandURLString(),
 				Description: random.AlphaNumeric(),
-				// Members
 			},
 			setup: func(f mockContestRepositoryFields, args args, want *domain.ContestTeamDetail) {
+				u := want.Members[0]
 				f.h.Mock.
 					ExpectQuery(makeSQLQueryRegexp("SELECT * FROM `contest_teams` WHERE `contest_teams`.`id` = ? AND `contest_teams`.`contest_id` = ? ORDER BY `contest_teams`.`id` LIMIT 1")).
 					WithArgs(args.teamID, args.contestID).
@@ -653,6 +692,36 @@ func TestContestRepository_GetContestTeam(t *testing.T) {
 						sqlmock.NewRows([]string{"id", "contest_id", "name", "result", "link", "description"}).
 							AddRow(want.ContestTeam.ID, want.ContestTeam.ContestID, want.ContestTeam.Name, want.ContestTeam.Result, want.Link, want.Description),
 					)
+
+				belongingRows := sqlmock.NewRows([]string{"team_id", "user_id"})
+				for _, u := range want.Members {
+					belongingRows.AddRow(args.teamID, u.ID)
+				}
+				f.h.Mock.
+					ExpectQuery(makeSQLQueryRegexp("SELECT * FROM `contest_team_user_belongings` WHERE `contest_team_user_belongings`.`team_id` = ?")).
+					WithArgs(args.teamID).
+					WillReturnRows(belongingRows)
+
+				userIDs := make([]driver.Value, len(want.Members))
+				userRows := sqlmock.NewRows([]string{"id", "name", "check"})
+				for i, u := range want.Members {
+					userIDs[i] = u.ID
+					userRows.AddRow(u.ID, u.Name, u.Check)
+				}
+				f.h.Mock.
+					ExpectQuery(makeSQLQueryRegexp("SELECT * FROM `users` WHERE `users`.`id` IN (?,?)")).
+					WithArgs(userIDs...).
+					WillReturnRows(userRows)
+
+				f.h.Mock.
+					ExpectQuery(makeSQLQueryRegexp("SELECT * FROM `users` WHERE `users`.`id` = ?")).
+					WithArgs(u.ID).
+					WillReturnRows(
+						sqlmock.NewRows([]string{"id", "name", "check"}).
+							AddRow(u.ID, u.Name, u.Check),
+					)
+
+				f.portal.EXPECT().GetUsers().Return(makePortalUsers(t, want.Members), nil)
 			},
 			assertion: assert.NoError,
 		},
@@ -718,14 +787,16 @@ func TestContestRepository_CreateContestTeam(t *testing.T) {
 			},
 			want: &domain.ContestTeamDetail{
 				ContestTeam: domain.ContestTeam{
-					// ID: Assertion時にgot.IDと合わせる
-					ContestID: cid,
-					Name:      successArgs.Name,
-					Result:    successArgs.Result.ValueOrZero(),
+					ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+						// ID: Assertion時にgot.IDと合わせる
+						ContestID: cid,
+						Name:      successArgs.Name,
+						Result:    successArgs.Result.ValueOrZero(),
+					},
+					Members: make([]*domain.User, 0),
 				},
 				Link:        successArgs.Link.ValueOrZero(),
 				Description: successArgs.Description,
-				Members:     nil,
 			},
 			setup: func(f mockContestRepositoryFields, args args, want *domain.ContestTeamDetail) {
 				f.h.Mock.
diff --git a/interfaces/repository/user_impl.go b/interfaces/repository/user_impl.go
index 68e23545..b700c9b9 100644
--- a/interfaces/repository/user_impl.go
+++ b/interfaces/repository/user_impl.go
@@ -529,7 +529,7 @@ func (r *UserRepository) GetContests(ctx context.Context, userID uuid.UUID) ([]*
 				Name:      ct.Contest.Name,
 				TimeStart: ct.Contest.Since,
 				TimeEnd:   ct.Contest.Until,
-				Teams:     []*domain.ContestTeam{},
+				Teams:     []*domain.ContestTeamWithoutMembers{},
 			}
 		}
 	}
@@ -537,7 +537,7 @@ func (r *UserRepository) GetContests(ctx context.Context, userID uuid.UUID) ([]*
 	for _, v := range contestTeamUserBelongings {
 		if userID == v.UserID {
 			ct := v.ContestTeam
-			contestsMap[ct.ContestID].Teams = append(contestsMap[ct.ContestID].Teams, &domain.ContestTeam{
+			contestsMap[ct.ContestID].Teams = append(contestsMap[ct.ContestID].Teams, &domain.ContestTeamWithoutMembers{
 				ID:        ct.ID,
 				ContestID: ct.ContestID,
 				Name:      ct.Name,
diff --git a/interfaces/repository/user_impl_test.go b/interfaces/repository/user_impl_test.go
index 9f95a466..0accb8bd 100644
--- a/interfaces/repository/user_impl_test.go
+++ b/interfaces/repository/user_impl_test.go
@@ -1466,7 +1466,7 @@ func TestUserRepository_GetContests(t *testing.T) {
 					Name:      random.AlphaNumeric(),
 					TimeStart: random.Time(),
 					TimeEnd:   random.Time(),
-					Teams: []*domain.ContestTeam{
+					Teams: []*domain.ContestTeamWithoutMembers{
 						{
 							ID:        random.UUID(),
 							ContestID: cid,
@@ -1518,7 +1518,7 @@ func TestUserRepository_GetContests(t *testing.T) {
 					Name:      random.AlphaNumeric(),
 					TimeStart: random.Time(),
 					TimeEnd:   random.Time(),
-					Teams: []*domain.ContestTeam{
+					Teams: []*domain.ContestTeamWithoutMembers{
 						{
 							ID:        random.UUID(),
 							ContestID: cid,
diff --git a/usecases/service/contest_test.go b/usecases/service/contest_test.go
index 8f1bb750..40039b59 100644
--- a/usecases/service/contest_test.go
+++ b/usecases/service/contest_test.go
@@ -118,10 +118,12 @@ func TestContestService_GetContest(t *testing.T) {
 				Description: random.AlphaNumeric(),
 				ContestTeams: []*domain.ContestTeam{
 					{
-						ID:        random.UUID(),
-						ContestID: cid,
-						Name:      random.AlphaNumeric(),
-						Result:    random.AlphaNumeric(),
+						ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+							ID:        random.UUID(),
+							ContestID: cid,
+							Name:      random.AlphaNumeric(),
+							Result:    random.AlphaNumeric(),
+						},
 					},
 				},
 			},
@@ -449,10 +451,12 @@ func TestContestService_GetContestTeams(t *testing.T) {
 			},
 			want: []*domain.ContestTeam{
 				{
-					ID:        random.UUID(),
-					ContestID: cid,
-					Name:      random.AlphaNumeric(),
-					Result:    random.AlphaNumeric(),
+					ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+						ID:        random.UUID(),
+						ContestID: cid,
+						Name:      random.AlphaNumeric(),
+						Result:    random.AlphaNumeric(),
+					},
 				},
 			},
 			setup: func(f fields, args args, want []*domain.ContestTeam) {
@@ -524,25 +528,29 @@ func Test_contestService_GetContestTeam(t *testing.T) {
 			},
 			want: &domain.ContestTeamDetail{
 				ContestTeam: domain.ContestTeam{
-					ID:        tid,
-					ContestID: cid,
-					Name:      random.AlphaNumeric(),
-					Result:    random.AlphaNumeric(),
+					ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+						ID:        tid,
+						ContestID: cid,
+						Name:      random.AlphaNumeric(),
+						Result:    random.AlphaNumeric(),
+					},
+					Members: []*domain.User{
+						domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), random.Bool()),
+					},
 				},
 				Link:        random.RandURLString(),
 				Description: random.AlphaNumeric(),
-				Members: []*domain.User{
-					domain.NewUser(random.UUID(), random.AlphaNumeric(), random.AlphaNumeric(), random.Bool()),
-				},
 			},
 			setup: func(f fields, args args, want *domain.ContestTeamDetail) {
 				repo := f.repo.(*mock_repository.MockContestRepository)
 				repo.EXPECT().GetContestTeam(args.ctx, args.contestID, args.teamID).Return(&domain.ContestTeamDetail{
 					ContestTeam: domain.ContestTeam{
-						ID:        args.teamID,
-						ContestID: args.contestID,
-						Name:      want.Name,
-						Result:    want.Result,
+						ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+							ID:        args.teamID,
+							ContestID: args.contestID,
+							Name:      want.Name,
+							Result:    want.Result,
+						},
 					},
 					Link:        want.Link,
 					Description: want.Description,
@@ -577,10 +585,12 @@ func Test_contestService_GetContestTeam(t *testing.T) {
 				repo := f.repo.(*mock_repository.MockContestRepository)
 				repo.EXPECT().GetContestTeam(args.ctx, args.contestID, args.teamID).Return(&domain.ContestTeamDetail{
 					ContestTeam: domain.ContestTeam{
-						ID:        args.teamID,
-						ContestID: args.contestID,
-						Name:      random.AlphaNumeric(),
-						Result:    random.AlphaNumeric(),
+						ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+							ID:        args.teamID,
+							ContestID: args.contestID,
+							Name:      random.AlphaNumeric(),
+							Result:    random.AlphaNumeric(),
+						},
 					},
 					Link:        random.RandURLString(),
 					Description: random.AlphaNumeric(),
@@ -650,27 +660,31 @@ func TestContestService_CreateContestTeam(t *testing.T) {
 			},
 			want: &domain.ContestTeamDetail{
 				ContestTeam: domain.ContestTeam{
-					ID:        tid,
-					ContestID: cid,
-					Name:      name,
-					Result:    result,
+					ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+						ID:        tid,
+						ContestID: cid,
+						Name:      name,
+						Result:    result,
+					},
+					Members: nil,
 				},
 				Link:        link,
 				Description: description,
-				Members:     nil,
 			},
 			setup: func(f fields, args args, want *domain.ContestTeamDetail) {
 				repo := f.repo.(*mock_repository.MockContestRepository)
 				repo.EXPECT().CreateContestTeam(args.ctx, args.contestID, args.args).Return(&domain.ContestTeamDetail{
 					ContestTeam: domain.ContestTeam{
-						ID:        tid,
-						ContestID: args.contestID,
-						Name:      args.args.Name,
-						Result:    args.args.Result.ValueOrZero(),
+						ContestTeamWithoutMembers: domain.ContestTeamWithoutMembers{
+							ID:        tid,
+							ContestID: args.contestID,
+							Name:      args.args.Name,
+							Result:    args.args.Result.ValueOrZero(),
+						},
+						Members: nil,
 					},
 					Link:        args.args.Link.ValueOrZero(),
 					Description: args.args.Description,
-					Members:     nil,
 				}, nil)
 			},
 			assertion: assert.NoError,
diff --git a/usecases/service/user_test.go b/usecases/service/user_test.go
index cbef07d2..54959297 100644
--- a/usecases/service/user_test.go
+++ b/usecases/service/user_test.go
@@ -573,7 +573,7 @@ func TestUserService_GetUserContests(t *testing.T) {
 					Name:      random.AlphaNumeric(),
 					TimeStart: random.Time(),
 					TimeEnd:   random.Time(),
-					Teams: []*domain.ContestTeam{
+					Teams: []*domain.ContestTeamWithoutMembers{
 						{
 							ID:     random.UUID(),
 							Name:   random.AlphaNumeric(),
diff --git a/util/mockdata/handler.go b/util/mockdata/handler.go
index de56d8fe..2a962885 100644
--- a/util/mockdata/handler.go
+++ b/util/mockdata/handler.go
@@ -7,38 +7,45 @@ import (
 )
 
 var (
-	HMockContestDetails   = CloneHandlerMockContestDetails()
-	HMockContests         = CloneHandlerMockContests()
-	HMockContestTeamsByID = CloneHandlerMockContestTeamsByID()
-	HMockEvents           = CloneHandlerMockEvents()
-	HMockEventDetails     = CloneHandlerMockEventDetails()
-	HMockGroups           = CloneHandlerMockGroups()
-	HMockGroupMembersByID = CloneHandlerMockGroupMembersByID()
-	HMockProjects         = CloneHandlerMockProjects()
-	HMockProjectDetails   = CloneHandlerMockProjectDetails()
-	HMockProjectMembers   = CloneHandlerMockProjectMembers()
-	HMockUsers            = CloneHandlerMockUsers()
-	HMockUserDetails      = CloneHandlerMockUserDetails()
-	HMockUserAccountsByID = CloneHandlerMockUserAccountsByID()
-	HMockUserEvents       = CloneHandlerMockUserEvents()
-	HMockUserContestsByID = CloneHandlerMockUserContestsByID()
-	HMockUserGroupsByID   = CloneHandlerMockUserGroupsByID()
-	HMockUserProjects     = CloneHandlerMockUserProjects()
+	HMockContestDetails         = CloneHandlerMockContestDetails()
+	HMockContests               = CloneHandlerMockContests()
+	HMockContestTeamsByID       = CloneHandlerMockContestTeamsByID()
+	HMockContestTeamMembersByID = CloneHandlerMockContestTeamMembersByID()
+	HMockEvents                 = CloneHandlerMockEvents()
+	HMockEventDetails           = CloneHandlerMockEventDetails()
+	HMockGroups                 = CloneHandlerMockGroups()
+	HMockGroupMembersByID       = CloneHandlerMockGroupMembersByID()
+	HMockProjects               = CloneHandlerMockProjects()
+	HMockProjectDetails         = CloneHandlerMockProjectDetails()
+	HMockProjectMembers         = CloneHandlerMockProjectMembers()
+	HMockUsers                  = CloneHandlerMockUsers()
+	HMockUserDetails            = CloneHandlerMockUserDetails()
+	HMockUserAccountsByID       = CloneHandlerMockUserAccountsByID()
+	HMockUserEvents             = CloneHandlerMockUserEvents()
+	HMockUserContestsByID       = CloneHandlerMockUserContestsByID()
+	HMockUserGroupsByID         = CloneHandlerMockUserGroupsByID()
+	HMockUserProjects           = CloneHandlerMockUserProjects()
 )
 
 func CloneHandlerMockContestDetails() []schema.ContestDetail {
 	var (
-		mContests       = CloneMockContests()
-		hContestTeams   = CloneMockContestTeams()
-		mContestTeams   = make([]schema.ContestTeam, len(hContestTeams))
-		hContestDetails = make([]schema.ContestDetail, len(mContests))
+		mContests        = CloneMockContests()
+		hContestTeams    = CloneMockContestTeams()
+		hTeamMembersByID = CloneHandlerMockContestTeamMembersByID()
+		mContestTeams    = make([]schema.ContestTeam, len(hContestTeams))
+		hContestDetails  = make([]schema.ContestDetail, len(mContests))
 	)
 
 	for i, c := range hContestTeams {
+		members, ok := hTeamMembersByID[c.ID]
+		if !ok {
+			members = make([]schema.User, 0)
+		}
 		mContestTeams[i] = schema.ContestTeam{
-			Id:     c.ID,
-			Name:   c.Name,
-			Result: c.Result,
+			Id:      c.ID,
+			Members: members,
+			Name:    c.Name,
+			Result:  c.Result,
 		}
 	}
 
@@ -80,19 +87,53 @@ func CloneHandlerMockContests() []schema.Contest {
 func CloneHandlerMockContestTeamsByID() map[uuid.UUID][]schema.ContestTeam {
 	var (
 		mContestTeams     = CloneMockContestTeams()
+		hTeamMembersByID  = CloneHandlerMockContestTeamMembersByID()
 		hContestTeamsByID = make(map[uuid.UUID][]schema.ContestTeam)
 	)
 
 	for _, ct := range mContestTeams {
+		members, ok := hTeamMembersByID[ct.ID]
+		if !ok {
+			members = make([]schema.User, 0)
+		}
 		hContestTeamsByID[ct.ContestID] = append(hContestTeamsByID[ct.ContestID], schema.ContestTeam{
-			Id:     ct.ID,
-			Name:   ct.Name,
-			Result: ct.Result,
+			Id:      ct.ID,
+			Members: members,
+			Name:    ct.Name,
+			Result:  ct.Result,
 		})
 	}
 	return hContestTeamsByID
 }
 
+func CloneHandlerMockContestTeamMembersByID() map[uuid.UUID][]schema.User {
+	var (
+		hContestTeams         = CloneMockContestTeams()
+		mockMembersBelongings = CloneMockContestTeamUserBelongings()
+		mockMembers           = CloneMockUsers()
+		portalUsers           = CloneMockPortalUsers()
+		hContestMembers       = make(map[uuid.UUID][]schema.User, len(hContestTeams))
+	)
+
+	for _, c := range hContestTeams {
+		for _, ct := range mockMembersBelongings {
+			if c.ID == ct.TeamID {
+				for i, cm := range mockMembers {
+					if ct.UserID == cm.ID {
+						hContestMembers[ct.TeamID] = append(hContestMembers[c.ID], schema.User{
+							Id:       cm.ID,
+							Name:     cm.Name,
+							RealName: portalUsers[i].RealName,
+						})
+					}
+				}
+			}
+		}
+	}
+
+	return hContestMembers
+}
+
 func CloneHandlerMockEvents() []schema.Event {
 	var (
 		eventDetails = CloneHandlerMockEventDetails()
@@ -401,11 +442,11 @@ func CloneHandlerMockUserContestsByID() map[uuid.UUID][]schema.UserContest {
 	)
 
 	// userContestTeams[userID][contestID] = []ContestTeam
-	userContestTeams := make(map[uuid.UUID]map[uuid.UUID][]schema.ContestTeam, len(mUsers))
+	userContestTeams := make(map[uuid.UUID]map[uuid.UUID][]schema.ContestTeamWithoutMembers, len(mUsers))
 	for _, u := range mUsers {
-		userContestTeams[u.ID] = make(map[uuid.UUID][]schema.ContestTeam, len(hContests))
+		userContestTeams[u.ID] = make(map[uuid.UUID][]schema.ContestTeamWithoutMembers, len(hContests))
 		for _, c := range hContests {
-			userContestTeams[u.ID][c.Id] = []schema.ContestTeam{}
+			userContestTeams[u.ID][c.Id] = []schema.ContestTeamWithoutMembers{}
 			for _, ct := range mContestTeams {
 				if ct.ContestID != c.Id {
 					continue
@@ -416,7 +457,7 @@ func CloneHandlerMockUserContestsByID() map[uuid.UUID][]schema.UserContest {
 						continue
 					}
 
-					userContestTeams[u.ID][c.Id] = append(userContestTeams[u.ID][c.Id], schema.ContestTeam{
+					userContestTeams[u.ID][c.Id] = append(userContestTeams[u.ID][c.Id], schema.ContestTeamWithoutMembers{
 						Id:     ct.ID,
 						Name:   ct.Name,
 						Result: ct.Result,