An actuator, especially for a motor vehicle clutch, is of the kind that has a casing carrying a reversible electric motor which has a drive spindle, a driving element for coupling the actuator to an actuating member of the clutch, a coupling mechanism which couples the motor drive spindle to the driving element and which includes a toothed sector plate coupled in rotation to the driving element. The coupling mechanism also includes an actuating force reducing mechanism having a compensating spring. The actuating force reducing mechansim includes a compensating lever which is articulated on the toothed sector plate and on an intermediate pivoting lever, which is itself articulated to the casing, the intermediate pivoting lever being coupled to the compensating spring.