To provide an auxiliary driving device that can reduce the number of part items and can be downsized.

An auxiliary driving device 2 includes: a drive plate 14 that externally outputs the power generated by an engine 10 being the power source at the time of a vehicle 1 running; a clutch 54 provided in a power transmission path 50 for transmitting the power generated by the engine 10 to the drive wheel 56 side of the vehicle 1 to switch the transmission and shutoff of the power; and an auxiliary drive shaft 70 that can receive the rotary torque from the a position on the more drive wheel 56 side than the clutch 54 in the power transmission path 50 and the drive plate 14 and that can drive the auxiliary machine of the vehicle 1 by the rotary torque.