An actuator for a vehicle door lock mechanism has a motor, a first gear, a second gear and a third gear. The motor has a shaft to which the first gear is connected. The motor rotates the first gear, which in turn drives the second gear and the third gear. A non-tooth part is formed on the second gear. A projection is formed on the third gear. Stops are arranged for stopping rotation of the third gear. When the second gear rotates to a position where the non-tooth part corresponds to the third gear, the projection is spaced from one stop by an angle. When the second gear rotates further, the gears re-mesh and the third gear rotates till the projection contacts the stop.