diff --git a/lib/racc/parser.rb b/lib/racc/parser.rb
index f284c02307fcf5..0cdb42e49d1428 100644
--- a/lib/racc/parser.rb
+++ b/lib/racc/parser.rb
@@ -187,7 +187,7 @@ class Parser
     Racc_Runtime_Core_Version_R = '1.4.6'
     Racc_Runtime_Core_Revision_R = %w$originalRevision: 1.8 $[1]
     begin
-      require_relative 'cparse'
+      require 'racc/cparse'
     # Racc_Runtime_Core_Version_C  = (defined in extension)
       Racc_Runtime_Core_Revision_C = Racc_Runtime_Core_Id_C.split[2]
       unless new.respond_to?(:_racc_do_parse_c, true)