A lifter for a laundry treating apparatus includes a first member mounted at an inner side of a drum; and a second member mounted on the first member and protruded toward an inside of the drum, wherein the first member includes a hook protruded and formed along a circumference of the first member, at least part of which is disposed to cover an inner circumferential surface of the drum when inserted into a fastening hole of the drum and then slid in one direction; and a shield protruded and formed at an inner side of the first member and configured to completely cover the fastening hole when the hook is inserted into the fastening hole and then slid in one direction.