diff --git a/include/mruby/boxing_word.h b/include/mruby/boxing_word.h
index cde823c29..b39307e33 100644
--- a/include/mruby/boxing_word.h
+++ b/include/mruby/boxing_word.h
@@ -219,31 +219,13 @@ mrb_integer_func(mrb_value o) {
 MRB_INLINE enum mrb_vtype
 mrb_type(mrb_value o)
 {
-  switch (o.w & 0x07) {
-  case 0x00:
-    return (o.w == 0) ? MRB_TT_FALSE : mrb_val_union(o).bp->tt;
-  case 0x02: case 0x06:
-#ifdef MRB_WORDBOX_NO_FLOAT_TRUNCATE
-    return MRB_TT_SYMBOL;
-#else
-    return MRB_TT_FLOAT;
-#endif
-  case 0x04:
-    switch (o.w) {
-    case 0x04:
-      return MRB_TT_FALSE;
-    case 0x0c:
-      return MRB_TT_TRUE;
-    case 0x14:
-      return MRB_TT_UNDEF;
-    default:
-      /* SHALL NOT be reached if MRB_WORDBOX_NO_FLOAT_TRUNCATE is defined */
-      return MRB_TT_SYMBOL;
-    }
-  case 0x01: case 0x03: case 0x05: case 0x07:
-  default:
-    return MRB_TT_INTEGER;
-  }
+  return !mrb_bool(o)    ? MRB_TT_FALSE :
+         mrb_true_p(o)   ? MRB_TT_TRUE :
+         mrb_fixnum_p(o) ? MRB_TT_INTEGER :
+         mrb_symbol_p(o) ? MRB_TT_SYMBOL :
+         mrb_undef_p(o)  ? MRB_TT_UNDEF :
+         mrb_float_p(o)  ? MRB_TT_FLOAT :
+         mrb_val_union(o).bp->tt;
 }
 
 MRB_INLINE enum mrb_vtype