diff --git a/ChangeLog b/ChangeLog
index 175b315f23..af80895d0b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Wed May 28 23:04:35 2014  Tanaka Akira  <akr@fsij.org>
+
+	* test/ruby/test_io.rb (test_flush_in_finalizer1): Use
+	  ObjectSpace.each_object to close files.
+	  GC.start is not reliable.
+
 Wed May 28 19:00:31 2014  Tanaka Akira  <akr@fsij.org>
 
 	* lib/net/imap.rb (Net::IMAP#initialize): Close the opened socket when
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index b104086d43..9d2ecef725 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -2358,6 +2358,7 @@ End
       assert_nothing_raised(TypeError, bug3910) do
         500.times {
           f = File.open(path, "w")
+          f.instance_variable_set(:@test_flush_in_finalizer1, true)
           fds << f.fileno
           f.print "hoge"
         }
@@ -2365,7 +2366,11 @@ End
       t
     }
   ensure
-    GC.start
+    ObjectSpace.each_object(File) {|f|
+      if f.instance_variables.include?(:@test_flush_in_finalizer1)
+        f.close
+      end
+    }
     t.close!
   end