diff --git a/ChangeLog b/ChangeLog
index bae66616bb..18485a0156 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Jan  9 19:40:20 2012  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* test/zlib/test_zlib.rb (TestZlibGzipWriter#test_writer_wrap): set
+	  binmode explicitly.
+
 Mon Jan  9 14:42:41 2012  Narihiro Nakamura  <authornari@gmail.com>
 
 	* gc.c: free_slots is changed Singly linked list. clear
diff --git a/test/zlib/test_zlib.rb b/test/zlib/test_zlib.rb
index 37781bc8e7..4149c8aa8e 100644
--- a/test/zlib/test_zlib.rb
+++ b/test/zlib/test_zlib.rb
@@ -760,6 +760,7 @@ if defined? Zlib
 
     def test_writer_wrap
       t = Tempfile.new("test_zlib_gzip_writer_wrap")
+      t.binmode
       Zlib::GzipWriter.wrap(t) {|gz| gz.print("foo") }
       t.close
       assert_equal("foo", Zlib::GzipReader.open(t.path) {|gz| gz.read })