diff --git a/lib/matrix.rb b/lib/matrix.rb
index 980d3dfb78..5cc9697714 100644
--- a/lib/matrix.rb
+++ b/lib/matrix.rb
@@ -12,7 +12,7 @@
 # Original Documentation:: Gavin Sinclair (sourced from <i>Ruby in a Nutshell</i> (Matsumoto, O'Reilly))
 ##
 
-require "e2mmap.rb"
+require "e2mmap"
 
 module ExceptionForMatrix # :nodoc:
   extend Exception2MessageMapper
diff --git a/lib/thwait.rb b/lib/thwait.rb
index 8f9e0c2a78..541fe1e3c3 100644
--- a/lib/thwait.rb
+++ b/lib/thwait.rb
@@ -5,7 +5,7 @@
 #       $Revision: 1.3 $
 #       by Keiju ISHITSUKA(Nihon Rational Software Co.,Ltd.)
 
-require "e2mmap.rb"
+require "e2mmap"
 
 #
 # This class watches for termination of multiple threads.  Basic functionality