A motor device may include a motor including a motor shaft protruded from a motor main body; a worm gear connected with the motor shaft through a transmission mechanism and is formed with a spiral groove; and a worm wheel engaged with the worm gear. The transmission mechanism may include a transmission member to transmit rotation of the motor shaft to the worm gear. One end face on the motor main body side of the worm gear and an end face on a worm gear side of the transmission member may be formed with two protruded parts protruded toward the other of the end faces, and a recessed part engaged with the protruded parts is formed in the other of the end faces. A compression coil spring may disposed between the worm gear and the transmission member between the two protruded parts.