diff --git a/ChangeLog b/ChangeLog
index 12fa2e72c0..49e9ccc6ea 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Sep 17 11:09:21 2014  SHIBATA Hiroshi  <shibata.hiroshi@gmail.com>
+
+	* tool/rbinstall.rb: fixed invalid options with latest rubygems.
+	  https://github.com/rubygems/rubygems/issues/1013
+
 Tue Sep 16 19:19:00 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* benchmark/bm_app_aobench.rb: update outdated links to the
diff --git a/tool/rbinstall.rb b/tool/rbinstall.rb
index 08a577ebaa..8776bcd386 100755
--- a/tool/rbinstall.rb
+++ b/tool/rbinstall.rb
@@ -714,7 +714,7 @@ install?(:ext, :comm, :gem) do
   directories = Gem.ensure_gem_subdirectories(gem_dir, :mode => $dir_mode)
   prepare "bundle gems", gem_dir, directories
   Dir.glob(srcdir+'/gems/*.gem').each do |gem|
-    Gem.install gem, :install_dir => with_destdir(Gem.dir), :domain => :local, :ignore_dependencies => true
+    Gem.install gem, Gem::Requirement.default, :install_dir => with_destdir(Gem.dir), :domain => :local, :ignore_dependencies => true
     gemname = Pathname(gem).basename
     puts "#{" "*30}#{gemname}"
   end