The invention provides an electrically rotational adjusting unit, especially for an indirect visual system for vehicles. The electrically rotational adjusting unit can be made by using components with low stability. The invention provides a coupling device. In a neutral position in which the electric motor of the electric rotary actuator is deactivated, the coupling device couples a base member to a rotating member in a rotationally fixed manner and the electric rotary actuator is uncoupled to the rotating member. When the electric rotary actuator is activated, the base member is uncoupled from the rotating member, and the electric rotary actuator is coupled to the rotating member. Therefore, the forces and moments occurring during normal use are transmitted directly between the base member and the rotating member. The electric rotary actuator is activated for only a short time or for a period of time during which it can be ensured that no excessive force is being exerted on the base member and the rotating member. Consequently, the electric rotary actuator can be designed to be appropriately small and to withstand only comparatively small forces and moments.