diff --git a/test/-ext-/win32/test_dln.rb b/test/-ext-/win32/test_dln.rb
index 3624346a56..e8f68ac4d4 100644
--- a/test/-ext-/win32/test_dln.rb
+++ b/test/-ext-/win32/test_dln.rb
@@ -11,7 +11,7 @@ module Bug
         so = ::File.expand_path("../ext/-test-/win32/dln/dlntest.dll", ::EnvUtil.rubybin)
         assert_send([::File, :file?, so])
         path = ::ENV['PATH']
-        path = ::File.dirname(so) + ::RbConfig::CONFIG["PATH_SEPARATOR"] + path
+        path = ::File.dirname(so) + ::File::PATH_SEPARATOR + path
         assert_in_out_err([{'PATH'=>path}, '-r-test-/win32/dln', '-eexit'], '', [], [], bug, timeout: 10)
       end