diff --git a/extlib/benz/dict.c b/extlib/benz/dict.c
index 80aed488..656547d1 100644
--- a/extlib/benz/dict.c
+++ b/extlib/benz/dict.c
@@ -3,6 +3,7 @@
  */
 
 #include "picrin.h"
+#include "picrin/object.h"
 
 KHASH_DEFINE(dict, pic_sym *, pic_value, kh_ptr_hash_func, kh_ptr_hash_equal)
 
diff --git a/extlib/benz/include/picrin.h b/extlib/benz/include/picrin.h
index 177b877b..27fdc140 100644
--- a/extlib/benz/include/picrin.h
+++ b/extlib/benz/include/picrin.h
@@ -261,7 +261,6 @@ int pic_str_hash(pic_state *, struct pic_string *);
 
 #include "picrin/cont.h"
 #include "picrin/data.h"
-#include "picrin/dict.h"
 #include "picrin/error.h"
 #include "picrin/macro.h"
 #include "picrin/pair.h"
diff --git a/extlib/benz/include/picrin/dict.h b/extlib/benz/include/picrin/dict.h
deleted file mode 100644
index bcb3a427..00000000
--- a/extlib/benz/include/picrin/dict.h
+++ /dev/null
@@ -1,25 +0,0 @@
-/**
- * See Copyright Notice in picrin.h
- */
-
-#ifndef PICRIN_DICT_H
-#define PICRIN_DICT_H
-
-#if defined(__cplusplus)
-extern "C" {
-#endif
-
-KHASH_DECLARE(dict, pic_sym *, pic_value)
-
-struct pic_dict {
-  PIC_OBJECT_HEADER
-  khash_t(dict) hash;
-};
-
-#define pic_dict_ptr(v) ((struct pic_dict *)pic_obj_ptr(v))
-
-#if defined(__cplusplus)
-}
-#endif
-
-#endif
diff --git a/extlib/benz/include/picrin/object.h b/extlib/benz/include/picrin/object.h
index 6a5d5b16..2a4c7caf 100644
--- a/extlib/benz/include/picrin/object.h
+++ b/extlib/benz/include/picrin/object.h
@@ -44,6 +44,18 @@ struct pic_vector {
 #define pic_vec_ptr(o) ((struct pic_vector *)pic_obj_ptr(o))
 
 
+/* dictionary */
+
+KHASH_DECLARE(dict, pic_sym *, pic_value)
+
+struct pic_dict {
+  PIC_OBJECT_HEADER
+  khash_t(dict) hash;
+};
+
+#define pic_dict_ptr(v) ((struct pic_dict *)pic_obj_ptr(v))
+
+
 /* weak */
 
 KHASH_DECLARE(weak, void *, pic_value)