In a back rest for a vehicle seat, the upholstery support is provided at least in one upper corner area in its front side with an opening to form a receptacle for a belt retraction device, which receptacle is open toward the front and closed at the rear by a back wall lying behind and spaced from the front side. An upper and a lower wall, which form the top and bottom of the receptacle, are connected with the front wall and/or the back wall and are spaced from each other so as to allow the receptacle to receive the belt retraction device without play. Form-fitting, overlapping restraining elements on the upper wall and the facing upper side of the belt retraction device, as well as on the back wall and the facing back side of the belt retraction device, together with a connecting element that engages the underside of the belt retraction device, secure the retraction device against being moved out of the receptacle.