The invention relates to an actuator unit (1), in particular an exterior mirror actuator unit for an exterior mirror unit for a motor vehicle. The actuator unit (1) comprises en electric motor (2) having a driven drive shaft (20) on which a spiral gear (3) is fixedly clamped. The spiral gear can for instance be a worm or a gear with evoloid-evolvent toothing, but may alternatively also,have a different toothing. The spiral gear comprises a gear body (30) and at least one insert piece (31) situated at least partly in the gear body, with the aid of which insert piece the spiral gear is fixedly clamped on the drive shaft (20) of the electric motor (2).
