diff --git a/ChangeLog b/ChangeLog
index cc6d491989..96f3312f95 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Aug 26 11:39:01 2014  SHIBATA Hiroshi  <shibata.hiroshi@gmail.com>
+
+	* lib/thwait.rb (ThreadsWait): removed needless constant.
+
 Tue Aug 26 09:27:10 2014  SHIBATA Hiroshi  <shibata.hiroshi@gmail.com>
 
 	* lib/mathn.rb: mathn library is deprecated on ruby 2.2.
diff --git a/lib/thwait.rb b/lib/thwait.rb
index f6bf314b4b..60f3911887 100644
--- a/lib/thwait.rb
+++ b/lib/thwait.rb
@@ -25,8 +25,6 @@ require "e2mmap.rb"
 #
 #
 class ThreadsWait
-  RCS_ID='-$Id: thwait.rb,v 1.3 1998/06/26 03:19:34 keiju Exp keiju $-'
-
   extend Exception2MessageMapper
   def_exception("ErrNoWaitingThread", "No threads for waiting.")
   def_exception("ErrNoFinishedThread", "No finished threads.")