diff --git a/.gitignore b/.gitignore
index 08e2566..e8e9f57 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
-.ruby-version
+/coverage
 /zinbeijett.iml
+.ruby-version
 Gemfile.lock
\ No newline at end of file
diff --git a/Gemfile b/Gemfile
index aceff40..c1f6124 100644
--- a/Gemfile
+++ b/Gemfile
@@ -10,6 +10,7 @@ gem 'pry'
 gem 'rake'
 gem 'rspec'
 gem 'minitest'
+gem 'simplecov'
 #gem 'solargraph'
 #gem 'nokogiri'
 #gem 'httparty'
diff --git a/mini_test_runner.rb b/mini_test_runner.rb
index 1fb441c..46f8fbe 100644
--- a/mini_test_runner.rb
+++ b/mini_test_runner.rb
@@ -26,6 +26,7 @@ def remove
 
 # About Exception, begin ~ rescue ~ ensure.
 begin
+  SimpleCov.start
   MiniTestFile.new.remove
 rescue StandardError => e
   puts e.backtrace.tanraku_exit
diff --git a/req/minitest.rb b/req/minitest.rb
index 875b4ba..32e8840 100644
--- a/req/minitest.rb
+++ b/req/minitest.rb
@@ -7,4 +7,5 @@
 require 'minitest/runner'
 require 'himekurits'
 require 'tanraku'
+require 'simplecov'
 # --------------------------------------