diff --git a/ChangeLog b/ChangeLog
index 87cbad0091..f2ee984fa5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sat Oct 30 09:40:54 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* enum.c: use constants in id.h.
+
 Sat Oct 30 09:08:27 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ext/fiddle/closure.c (fiddle_closure): embed cif not reference
diff --git a/common.mk b/common.mk
index 22b8ff3cf4..80f058c3f2 100644
--- a/common.mk
+++ b/common.mk
@@ -549,7 +549,7 @@ dmyencoding.$(OBJEXT): {$(VPATH)}dmyencoding.c $(RUBY_H_INCLUDES) \
 encoding.$(OBJEXT): {$(VPATH)}encoding.c $(RUBY_H_INCLUDES) \
   $(ENCODING_H_INCLUDES) {$(VPATH)}regenc.h {$(VPATH)}util.h
 enum.$(OBJEXT): {$(VPATH)}enum.c $(RUBY_H_INCLUDES) {$(VPATH)}node.h \
-  {$(VPATH)}util.h
+  {$(VPATH)}util.h $(ID_H_INCLUDES)
 enumerator.$(OBJEXT): {$(VPATH)}enumerator.c $(RUBY_H_INCLUDES)
 error.$(OBJEXT): {$(VPATH)}error.c {$(VPATH)}known_errors.inc \
   $(RUBY_H_INCLUDES) $(VM_CORE_H_INCLUDES) $(ENCODING_H_INCLUDES) \
diff --git a/enum.c b/enum.c
index 8d4692ae6d..eade8cb25a 100644
--- a/enum.c
+++ b/enum.c
@@ -12,9 +12,13 @@
 #include "ruby/ruby.h"
 #include "ruby/util.h"
 #include "node.h"
+#include "id.h"
 
 VALUE rb_mEnumerable;
-static ID id_each, id_eqq, id_cmp, id_next, id_size;
+static ID id_next;
+#define id_each idEach
+#define id_eqq  idEqq
+#define id_cmp  idCmp
 
 static VALUE
 enum_values_pack(int argc, VALUE *argv)
@@ -2659,10 +2663,5 @@ Init_Enumerable(void)
     rb_define_method(rb_mEnumerable, "chunk", enum_chunk, -1);
     rb_define_method(rb_mEnumerable, "slice_before", enum_slice_before, -1);
 
-    id_eqq  = rb_intern("===");
-    id_each = rb_intern("each");
-    id_cmp  = rb_intern("<=>");
     id_next = rb_intern("next");
-    id_size = rb_intern("size");
 }
-