The invention relates to a hydraulic actuator comprising a variable-output positive-displacement pump (12), a member (20) allowing the output of the pump (12) to be varied continuously, the member (20) being actuated by a cylinder (40) fed from a first directional-control valve (48) operated according to a command controlling the movement of the actuator (10). According to the invention, the actuator (10) comprises a second directional-control valve (60) controlled according to an output pressure (P) of the pump (12), the second directional-control valve (60) having two positions, one of them (60a), known as the rest position, being obtained as long as the output pressure (P) of the pump (12) is below a predetermined pressure and transmitting the output from the first directional-control valve (48) to the double-acting cylinder (40), and the other (60b), known as the active position, transmitting the output pressure (P) of the pump (12) to the cylinder (40) in such a way as to reduce the output pressure (P) of the pump (12) without passing via the first directional-control valve (48).