diff --git a/mrbgems/mruby-bigint/core/bigint.c b/mrbgems/mruby-bigint/core/bigint.c
index 9a45ae504..8798b696c 100644
--- a/mrbgems/mruby-bigint/core/bigint.c
+++ b/mrbgems/mruby-bigint/core/bigint.c
@@ -1263,7 +1263,7 @@ bint_new(mrb_state *mrb, mpz_t *x)
   if (x->sz <= RBIGINT_EMBED_SIZE_MAX) {
     RBIGINT_SET_EMBED_SIZE(b, x->sz);
     RBIGINT_SET_EMBED_SIGN(b, x->sn);
-    memcpy(RBIGINT_EMBED_ARY(b), x->p, x->sz*sizeof(mp_limb));
+    if (x->p) memcpy(RBIGINT_EMBED_ARY(b), x->p, x->sz*sizeof(mp_limb));
     mpz_clear(mrb, x);
   }
   else {