A drive device which drives a driven device such as a lift mechanism (8) for lifting a window pane (9), comprising a motor (5) having a rotating shaft (13) and output units (6; 80) connected to the motor, wherein the output units are provided with speed reduction mechanisms (42, 43, 56; 56, 92) decelerating the rotation of the rotating shaft, clutches (21; 71; 81; 200; 300) are installed between the rotating shaft and the speed reduction mechanisms, the clutches allow a rotation to be transmitted from the rotating shaft to the speed reduction mechanisms and prevent the rotation from being transmitted from the speed reduction mechanisms to the rotating shaft, whereby a large load does not apply to the clutches disposed between the rotating shaft and the speed reduction mechanisms and, therefore, a strength required for the clutches can be reduced so as to reduce the size of the clutches.