Adjustment device for a vehicle seat for adjusting the angle of a backrest of the vehicle seat relative to a seat component

The device (1) has a fitting part (2) including a spline shaft-like molded form-fitting unit (3) in outer periphery. The molded form-fitting unit is inserted in a correspondingly formed receiver (8) of a seat component (4) under formation of a rotational mold closure. The fitting part is fixedly and/or force-fittingly arranged in a backrest of a vehicle seat, and the molded form-fitting unit is rotatably or pivotally held and/or mounted in the fitting part, and includes an axially running through-hole. The fitting part and the receiver are arranged in the vehicle seat.