An apparatus for opening and closing the car door of an elevator car which is situated in the door opening zone of a floor is coupled together with a shaft door, and is driven automatically by a drive motor or, in the case of a power failure, manually by a passenger. If the elevator car is situated outside a door opening zone, the car door remains locked by the same apparatus. The car door is driven through a drive belt by way of an entraining parallelogram linkage, which linkage includes a rigid cam and a movable cam and is mounted at the upper part of a car door. For free travel through a door opening zone, the linkage is closed, and the linkage opens for the coupling with the shaft door between two coupling rollers mounted on the shaft door before a movement of the doors takes place. The movable cam includes a compressible ramp cam which, during the travel and on stopping outside a door opening zone, lifts off from a rigid cam carrier due to leaf springs. On the coupling with the coupling rollers of a shaft door, the ramp cam is pressed against the rigid cam carrier for the unlocking of a car door bolt. The linkage is connected to the drive belt by an actuating lever which cooperates with a pair of abutments to define the open and closed positions of the linkage.