diff --git a/tool/test/test_jisx0208.rb b/tool/test/test_jisx0208.rb
index d323c84745..703ee36f58 100644
--- a/tool/test/test_jisx0208.rb
+++ b/tool/test/test_jisx0208.rb
@@ -1,6 +1,6 @@
 require 'test/unit'
 
-require '../tool/jisx0208'
+require_relative '../jisx0208'
 
 class Test_JISX0208_Char < Test::Unit::TestCase
   def test_create_with_row_cell