A polishing apparatus includes a polishing jig. The polishing jig includes an elastic balloon member, a fixture, and a fluid supply portion. The fixture airtightly closes the rear opening portion of the balloon member. The fluid supply portion supplies a fluid into a space formed by the fixture and balloon member. The balloon member has a cup shape constructed by a dome portion and a cylinder portion extending backward from the outer periphery of the dome portion. The fixture fixes the opening portion of the cylinder portion of the balloon member.