Provided is a hole plug for closing a through-hole provided in a body member. The hole plug comprises a flange part, a penetration part which is provided to hang from the flange part and penetrates the through-hole, and a meltable member which is mounted to the penetration part and interposed between the flange part and the body member. The hole plug has, on the outer peripheral surface of the penetration part, an engagement part for engaging with the body member, and a rib which hangs from the flange part to form a gap between the body member and the flange part.