diff --git a/tool/merger.rb b/tool/merger.rb
index 07ac6e6304..cfc3d58831 100755
--- a/tool/merger.rb
+++ b/tool/merger.rb
@@ -170,7 +170,7 @@ else
   system 'svn up'
   system 'ruby tool/file2lastrev.rb --revision.h . > revision.tmp'
   system 'tool/ifchange "--timestamp=.revision.time" "revision.h" "revision.tmp"'
-  FileUtils.rm('revision.tmp')
+  FileUtils.rm_f('revision.tmp')
 
   case ARGV[0]
   when /--ticket=(.*)/