diff --git a/spec/basic/step03_data_type_spec.rb b/spec/basic/step03_data_type_spec.rb
index 02e7b83..7a5ee66 100644
--- a/spec/basic/step03_data_type_spec.rb
+++ b/spec/basic/step03_data_type_spec.rb
@@ -6,7 +6,7 @@
   context 'basic type' do
     # What string is sea variable at the method end? <br>
     # (メソッド終了時の変数 sea の中身は？)
-    it 'spec datatype basic type' do
+    it 'datatype basic type' do
       sea = "mystic"
       land = 416
       piari = Date.new(2001, 9, 4)
@@ -29,7 +29,7 @@
 
   context 'object' do
     # Same as the previous method question. (前のメソッドの質問と同じ)
-    it 'spec datatype object' do
+    it 'datatype object' do
       stage = St3ImmutableStage.new("hangar")
       sea = stage.stage_name()
       log(sea) # your answer? =>
diff --git a/spec/basic/step04_method_spec.rb b/spec/basic/step04_method_spec.rb
new file mode 100644
index 0000000..4e18296
--- /dev/null
+++ b/spec/basic/step04_method_spec.rb
@@ -0,0 +1,136 @@
+require 'spec_helper'
+
+describe 'Step04MethodSpec' do
+  context 'method call' do
+    #  What string is sea variable at the method end? <br>
+    # (メソッド終了時の変数 sea の中身は？)
+    it 'method call basic' do
+      sea = supply_something
+      log(sea) # your answer? =>
+    end
+
+    it 'method call many' do
+      sea = function_something('mystic')
+      consume_something(supply_something)
+      runnable_something
+      log(sea) # your answer? => 
+    end
+
+    def function_something(name)
+      replaced = name.sub('tic', 'mys')
+      log("in function: #{replaced}")
+      replaced
+    end
+
+    def supply_something
+      sea = 'over'
+      log("in supply: #{sea}")
+      sea
+    end
+
+    def consume_something(sea)
+      log("in consume: #{sea.sub("over", "mystic")}")
+    end
+
+    def runnable_something
+      String sea = "outofshadow"
+      log("in runnable: #{sea}")
+    end
+
+    # Same as the previous method question. (前のメソッドの質問と同じ)
+    it 'method object' do
+      mutable = St4MutableStage.new
+      sea = 904
+      land = false
+      hello_mutable(sea - 4, land, mutable)
+      if !land
+        sea = sea + mutable.stage_name.length
+      end
+      log(sea) # your answer? => 
+    end
+
+    def hello_mutable(sea, land, piari)
+      sea += 1
+      land = true
+      piari.stage_name = 'mystic'
+      sea
+    end
+
+    class St4MutableStage
+      attr_accessor :stage_name
+    end
+  end
+
+  context 'instance variable' do
+    # Same as the previous method question. (前のメソッドの質問と同じ) */
+    it 'method instance variable' do
+      sea = St4InstanceVariableStage.new.spec
+      log(sea) # your answer? => 
+    end
+
+    class St4InstanceVariableStage
+      def initialize
+        @in_park_count = 0
+      end
+
+      def spec
+        @has_annual_passport = true
+        sea = @in_park_count
+        off_annual_passport(@has_annual_passport)
+        100.times do
+          go_to_park
+        end
+        sea += 1
+        sea = @in_park_count
+        sea
+      end
+
+      def off_annual_passport(has_annual_passport)
+        has_annual_passport = false
+      end
+
+      def go_to_park
+        if @has_annual_passport
+          @in_park_count += 1
+        end
+      end
+    end
+  end
+
+  context 'challenge' do
+    # Make private methods as followings, and comment out caller program in test method:
+    # <pre>
+    # o replace_a_to_b: has one argument as String, returns argument replaced "A" with "B" as String 
+    # o replace_c_to_b: has one argument as String, returns argument replaced "C" with "B" as String 
+    # o add_prefix: has two arguments as String, returns combined first argument with ":" with second argument 
+    # o available_logging?: no argument, returns private instance variable "available_logging" initialized as true (also make it)  
+    # o show_sea: has one argument as String argument, no return, show argument by log()
+    # </pre>
+    # (privateメソッドを以下のように定義して、テストメソッド内の呼び出しプログラムをコメントアウトしましょう):
+    # <pre>
+    # o replace_a_to_b: 一つのString引数、引数を "A" を "B" に置き換えらたStringを戻す 
+    # o replace_c_to_b: 一つのString引数、引数を "C" を "B" に置き換えらたStringを戻す 
+    # o add_prefix: 二つのString引数、第一引数と ":" と第二引数を連結したものを戻す 
+    # o available_logging?: 引数なし、privateのインスタンス変数 "availableLogging" (初期値:true) を戻す (それも作る)  
+    # o show_sea: 一つのString引数、戻り値なし、引数をlog()で表示する
+    # </pre>
+    it 'method making' do
+      # comment out after making these methods
+      # replaced = replace_c_to_b(replace_a_to_b('ABC'))
+      # sea = add_prefix('broadway', replaced)
+      # if St4ChallengeStage.new.available_logging?
+      #   show_sea(sea)
+      # end
+    end
+
+    # write methods here
+
+    class St4ChallengeStage
+      # write instance variables here
+
+      def available_logging?
+      end
+    end
+  end
+end
+