diff --git a/Gemfile b/Gemfile
index 81b90fc..f5697a4 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,4 +1,5 @@
 source "https://rubygems.org"
 
-# Specify your gem's dependencies in ipaddr.gemspec
-gemspec
+gem "bundler"
+gem "rake"
+gem "test-unit"
diff --git a/ipaddr.gemspec b/ipaddr.gemspec
index 96574bf..6b1cd13 100644
--- a/ipaddr.gemspec
+++ b/ipaddr.gemspec
@@ -21,8 +21,4 @@ Both IPv4 and IPv6 are supported.
   spec.require_paths = ["lib"]
 
   spec.required_ruby_version = "~> 2.3"
-
-  spec.add_development_dependency "bundler"
-  spec.add_development_dependency "rake", "~> 10.0"
-  spec.add_development_dependency "test-unit"
 end