diff --git a/ChangeLog b/ChangeLog
index c23b2df3a2..845eb852b4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Apr  2 03:35:25 2012  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* lib/webrick/server.rb (WEBrick::GenericServer): close socket only if
+	  the socket is not closed yet.
+
 Sun Apr  1 23:03:18 2012  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* lib/net/ftp.rb (Net::BufferedSocket): should delegate send() to @io
diff --git a/lib/webrick/server.rb b/lib/webrick/server.rb
index 30f4dc3143..c6d1e4f0f9 100644
--- a/lib/webrick/server.rb
+++ b/lib/webrick/server.rb
@@ -204,7 +204,7 @@ module WEBrick
           else
             @logger.debug "close: <address unknown>"
           end
-          sock.close
+          sock.close unless sock.closed?
         end
       }
     end