diff --git a/hash.c b/hash.c
index 172ed3bd49a..2686b913c33 100644
--- a/hash.c
+++ b/hash.c
@@ -1941,7 +1941,8 @@ rb_hash_init(rb_execution_context_t *ec, VALUE hash, VALUE capa_value, VALUE ifn
 
     if (capa_value != INT2FIX(0)) {
         long capa = NUM2LONG(capa_value);
-        if (capa > 0 && RHASH_AR_TABLE_P(hash) && RHASH_SIZE(hash) == 0 && capa > RHASH_AR_TABLE_MAX_BOUND(hash)) {
+        if (capa > 0 && RHASH_AR_TABLE_P(hash) && RHASH_SIZE(hash) == 0 &&
+            (unsigned long)capa > RHASH_AR_TABLE_MAX_BOUND(hash)) {
             hash_st_table_init(hash, capa);
         }
     }