A vehicle door drive unit for raising and lowering a glass plate is constructed so that a plurality of pulleys across which wires extend are provided at upper and lower sides of a base panel. The glass plate is supported by a carrier plate which is connected to the wire ends. The glass plate is moved up and down by the wires and is prevented from excessively moving in a vehicle inward direction when the door is closed by a supporting rod positioned along an upward and downward path of the glass plate and a contact member. Trumpet shaped guide portions are formed at the edges of holes of the wire fixing portions of the carrier plate and the circumferential surfaces of a V-shaped tensioner are provided for eliminating slack in the wires.