diff --git a/ChangeLog b/ChangeLog
index c9cf189027..ff69875ccb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sat Apr 11 23:26:05 2015  SHIBATA Hiroshi  <shibata.hiroshi@gmail.com>
+
+	* tool/rbinstall.rb: support destdir for native extention gem.
+
 Sat Apr 11 21:02:06 2015  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* test/ruby/test_file_exhaustive.rb
diff --git a/tool/rbinstall.rb b/tool/rbinstall.rb
index cec3b57f5c..1ce2983493 100755
--- a/tool/rbinstall.rb
+++ b/tool/rbinstall.rb
@@ -775,6 +775,7 @@ install?(:ext, :comm, :gem) do
   end
   next if gems.empty?
   if defined?(Zlib)
+    ENV['DESTDIR'] = $destdir if $destdir
     gems.each do |gem|
       Gem.install(gem, Gem::Requirement.default, options)
       gemname = File.basename(gem)