Control device for a tow bar and tow bar with a control device

The apparatus (40a) has a control device controlling and/or monitoring a drive (16) for adjustment of a coupling arm (12a) of a trailer coupling (10a) between a usage position (G) provided behind a rear end (91) of a towing vehicle (90) and a non-usage position adjusted behind a bumper. The control device controls and/or monitors an interlocking device (20a) interlocking the arm at a vehicle holder (11a). A coupling body (19) i.e. coupling ball, is arranged on the arm. The control device is held in a protective housing (41a) for arranging the control device in an outer region of the vehicle.