The driving device is provided with a motor, a pinion, a first gear, a second gear, and a frame. The frame has a motor side surface and a gear side surface, and includes a first portion and a second portion. A motor housing of the motor is fixed to and supported at the motor side surface of the first portion. A motor shaft extends from the motor housing, penetrating the first portion from the motor side surface to the gear side surface. The pinion is fixed to the distal end of the motor shaft at the gear side surface. The first gear and the second gear are coaxially disposed and rotatably supported at the gear side surface of the second portion. The driving force of the motor is transmitted to the first gear and the second gear through the pinion. The gear side surface of the second portion is offset toward the motor side than the motor side surface of the first portion.