diff --git a/ChangeLog b/ChangeLog
index dc20b6f7d3..54d3067c8d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,6 @@
-Wed Jul  8 17:13:36 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Wed Jul  8 18:28:04 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
-	* proc.c ({proc,method}_data_type): typed.
+	* proc.c ({proc,binding,method}_data_type): typed.
 
 Wed Jul  8 16:47:03 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
diff --git a/proc.c b/proc.c
index 04be7674c9..a1b2feea19 100644
--- a/proc.c
+++ b/proc.c
@@ -255,12 +255,25 @@ binding_mark(void *ptr)
     RUBY_MARK_LEAVE("binding");
 }
 
+static size_t
+binding_memsize(void *ptr)
+{
+    return ptr ? sizeof(rb_binding_t) : 0;
+}
+
+static const rb_data_type_t binding_data_type = {
+    "binding",
+    binding_mark,
+    binding_free,
+    binding_memsize,
+};
+
 static VALUE
 binding_alloc(VALUE klass)
 {
     VALUE obj;
     rb_binding_t *bind;
-    obj = Data_Make_Struct(klass, rb_binding_t, binding_mark, binding_free, bind);
+    obj = TypedData_Make_Struct(klass, rb_binding_t, &binding_data_type, bind);
     return obj;
 }