A hydraulic accumulator includes a limiting portion that is fitted into a ring end gap of a snap ring to limit a decrease in a diameter of the snap ring. The snap ring is stamped from a metal sheet by a press machine. Therefore, one of two opposed surfaces of a portion of the snap ring, which is fitted into a groove, forms a sloped surface as a result of shear droop. The limiting portion is fitted into the ring end gap of the snap ring to limit the decrease in the diameter of the snap ring. Thus, it is possible to limit riding of the sloped surface of the snap ring on a corner of the groove, and thereby it is possible to limit removal of the snap ring from the groove.