diff --git a/Gemfile b/Gemfile
index da5a84d..fa59d53 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,3 +7,9 @@ end
 
 # Specify your gem's dependencies in reline.gemspec
 gemspec
+
+group :development do
+  gem 'rake'
+  gem 'bundler'
+  gem 'reline'
+end
diff --git a/yamatanooroti.gemspec b/yamatanooroti.gemspec
index d30b7ac..16972ad 100644
--- a/yamatanooroti.gemspec
+++ b/yamatanooroti.gemspec
@@ -24,7 +24,4 @@ Gem::Specification.new do |spec|
   spec.required_ruby_version = Gem::Requirement.new('>= 2.5')
 
   spec.add_dependency 'test-unit'
-  spec.add_development_dependency 'rake'
-  spec.add_development_dependency 'bundler'
-  spec.add_development_dependency 'reline'
 end