A control device is provided for an actuator which includes an electric motor (32) fixed to a housing (33), a worm (34) rotated by the electric motor, a worm wheel (35) rotatably supported by the housing and meshed with the worm, a stop means (33a) contactable with the worm wheel when the worm wheel is rotated to an angle which is equal to or larger than a predetermined angle, and an electric control device for controlling an operation of the actuator. The control device further includes a driving means (46) for driving the electric motor, a contact judging means (41) for judging that the worm wheel is in contact with the stop means; and a memorizing means (45) for memorizing information corresponding to a rotation angle of the worm wheel as an initial position of the actuator when the judging means judges that the worm wheel is in contact with the stop means.