diff --git a/ChangeLog b/ChangeLog
index f812a3da0b..562e1db5b2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue May 21 03:08:52 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* test/ruby/envutil.rb (assert_separately): require envutil in the
+	  child process too.
+
 Tue May 21 03:07:26 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* string.c (rb_str_conv_enc_opts): should infect.
diff --git a/test/ruby/envutil.rb b/test/ruby/envutil.rb
index c80a5f7da9..ce7226f86d 100644
--- a/test/ruby/envutil.rb
+++ b/test/ruby/envutil.rb
@@ -1,6 +1,7 @@
 # -*- coding: us-ascii -*-
 require "open3"
 require "timeout"
+require "test/unit"
 
 module EnvUtil
   def rubybin
@@ -283,7 +284,7 @@ module Test
           line ||= loc.lineno
         end
         src = <<eom
-  require 'test/unit';include Test::Unit::Assertions;begin;#{src}
+  require #{__dir__.dump}'/envutil';include Test::Unit::Assertions;begin;#{src}
   ensure
     puts [Marshal.dump($!)].pack('m'), "assertions=\#{self._assertions}"
   end