A braking actuator for a hydraulic aircraft brake, received in a cavity of a ring of the brake. The actuator comprises a liner structure (1) sealed in the cavity of the ring, and a piston (3) slidably mounted in the liner structure to apply a braking force. A wear-compensating device (10) defines a retreated position of the piston in the liner structure by an axially movable stop (11) which can be advanced by the piston during the application of a braking force and in frictional relationship with a fixed part (18) of the wear-compensating device secured to the liner. An elastic member (24) returns the piston to the retreated position defined by the piston bearing against the movable stop, the movable stop being in frictional relationship with the fixed part via at least one telescopic intermediate element (16) interposed between the movable stop (11) and the fixed part (18).