diff --git a/include/mruby/proc.h b/include/mruby/proc.h
index 981e1111d..f8681b40b 100644
--- a/include/mruby/proc.h
+++ b/include/mruby/proc.h
@@ -133,7 +133,6 @@ MRB_API mrb_value mrb_proc_cfunc_env_get(mrb_state *mrb, mrb_int idx);
 
 
 #include <mruby/khash.h>
-KHASH_DECLARE(mt, mrb_sym, mrb_method_t, TRUE)
 
 MRB_API mrb_value mrb_load_proc(mrb_state *mrb, const struct RProc *proc);
 
diff --git a/mrbgems/mruby-symbol-ext/src/symbol.c b/mrbgems/mruby-symbol-ext/src/symbol.c
index f092b6e30..b631bffc1 100644
--- a/mrbgems/mruby-symbol-ext/src/symbol.c
+++ b/mrbgems/mruby-symbol-ext/src/symbol.c
@@ -1,5 +1,4 @@
 #include <mruby.h>
-#include <mruby/khash.h>
 #include <mruby/array.h>
 #include <mruby/string.h>