The invention provides an actuator for a control surface (7), in particular for a primary flight control of an aircraft, the actuator including a main actuator (3) in a main control line (1) for actuating the control surface (7), the actuator being characterized in that the actuator of the main control line (1) comprises a motor of the vibration motor type, and in that it further comprises, in a compensation, secondary control line (2), a compensation actuator (4) and spring-forming apparatus (5) interposed between the compensation actuator (4) and the control surface (7), the compensation actuator (4) tensioning or compressing the spring-forming apparatus so as to make them suitable for delivering a mean force to the control surface (7) so as to off-load from the main actuator (3) the mean force that it needs to deliver to the flight control (7).