Abstract: A rollback seal, which is used in a space between a piston and a housing of a hydraulic brake configured to brake a wheel by clamping a disc rotor fixedly attached to the wheel, is arranged in an annular groove of the housing, has a substantially rectangular sectional shape, has an annular recess formed in one end face thereof at the side where hydraulic pressure acts on the piston, and has a chamfered section formed at a piston side corner of the other end face thereof at the opposite side to that where the recess is formed, thereby to reduce total weight of brake system, secure sufficient amount of rollback at low temperature, and reliably return a piston from brake position to release position with improved sealing characteristics over a longer service life.