An actuating drive for an air deflector device on a vehicle includes a controllable electric motor having an output shaft; a step-down mechanism having a first worm drive and a second worm drive, the first worm drive being coupled by a first worm to the output shaft of the electric motor, the first worm drive having a worm wheel configured to be brought into operative connection with a worm of the second worm drive, the second worm drive having a worm wheel configured to drive the adjustment shaft for the air deflector device; and a mechanical actuating force transmitter configured to transmit an actuating force to the air deflector device.