An electrically actuated rotary drive device which has a gear casing with an electrical drive motor mounted at its rear side and on which is rotatably mounted an output member in driving connection with the drive motor. The driving connection is realised by gearing means provided in the gear casing and containing a driven gear fitted to the output member, in the form of a ring gear with internal tooth system, and a drive pinion belonging to the drive motor and with an external gear teeth system. The drive pinion extends into the ring gear, inside the gear casing.