diff --git a/src/array.c b/src/array.c
index dab869645..5a460428b 100644
--- a/src/array.c
+++ b/src/array.c
@@ -616,7 +616,7 @@ ary_replace(mrb_state *mrb, struct RArray *a, struct RArray *b)
     mrb_write_barrier(mrb, (struct RBasic*)a);
     return;
   }
-  if (!mrb_frozen_p(b) && len > ARY_REPLACE_SHARED_MIN) {
+  if (len > ARY_REPLACE_SHARED_MIN) {
     ary_make_shared(mrb, b);
     goto shared_b;
   }