diff --git a/ChangeLog b/ChangeLog
index 2d459863ee..52b878c75a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Jun 12 22:21:12 2015  Kazuhiro NISHIYAMA  <zn@mbf.nifty.com>
+
+	* test/ruby/test_extlibs.rb (TestExtLibs::check_existence): fix
+	  error. [Bug #11255] [ruby-dev:49079]
+
 Fri Jun 12 21:17:46 2015  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* pack.c (pack_{un,}pack): new template character `j` and `J`, pointer
diff --git a/test/ruby/test_extlibs.rb b/test/ruby/test_extlibs.rb
index 71dcf2b133..995baa0d32 100644
--- a/test/ruby/test_extlibs.rb
+++ b/test/ruby/test_extlibs.rb
@@ -13,7 +13,7 @@ class TestExtLibs < Test::Unit::TestCase
         log = #{log.dump}
         msg = proc {
           "extension library `#{ext}' is not found#{add_msg}\n" <<
-            (File.exist?(log) ? File.read(log) : "\#{log} not found")
+            (File.exist?(log) ? File.binread(log) : "\#{log} not found")
         }
         assert_nothing_raised(msg) do
           require "#{ext}"