diff --git a/ChangeLog b/ChangeLog
index c812e63710..81ffa49765 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Nov 21 18:02:10 2007  Koichi Sasada  <ko1@atdot.net>
+
+	* benchmark/driver.rb: add path to trunk/lib if driver runner is
+	  in build directory.
+
 Wed Nov 21 16:39:21 2007  Tanaka Akira  <akr@fsij.org>
 
 	* test/fileutils/fileasserts.rb (assert_equal_timestamp): new assert
diff --git a/benchmark/driver.rb b/benchmark/driver.rb
index 861d54f904..4a1afe360b 100644
--- a/benchmark/driver.rb
+++ b/benchmark/driver.rb
@@ -2,7 +2,22 @@
 # Ruby Benchmark driver
 #
 
-require 'optparse'
+first = true
+
+p RUBY_VERSION
+
+begin
+  require 'optparse'
+rescue LoadError
+  if first
+    first = false
+    $:.unshift File.join(File.dirname(__FILE__), '../lib')
+    retry
+  else
+    raise
+  end
+end
+
 require 'benchmark'
 require 'pp'