diff --git a/ChangeLog b/ChangeLog
index 631b9fed9b..ada66d5626 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Jul  2 10:30:01 2015  SHIBATA Hiroshi  <hsbt@ruby-lang.org>
+
+	* lib/rubygems/resolver.rb: fixed NameError of Gem::Util::NULL_DEVICE.
+
 Thu Jul  2 09:51:44 2015  SHIBATA Hiroshi  <hsbt@ruby-lang.org>
 
 	* lib/rubygems/resolver.rb: fix error of null device reference with DOSISH
diff --git a/lib/rubygems/resolver.rb b/lib/rubygems/resolver.rb
index fdb5ca9cf2..c56f224921 100644
--- a/lib/rubygems/resolver.rb
+++ b/lib/rubygems/resolver.rb
@@ -1,5 +1,6 @@
 require 'rubygems/dependency'
 require 'rubygems/exceptions'
+require 'rubygems/util'
 require 'rubygems/util/list'
 
 require 'uri'