An engine, an electric motor-generator, an oil pump, an air conditioner, and a first power transmitting means that performs power transmission among a crank shaft of the engine, a rotating shaft of the electric motor-generator, and rotating shafts of the oil pump and the air conditioner are included. The first power transmitting means has: a crank pulley; a first electric motor-generator pulley; an oil pump pulley; an air conditioner pulley; a first belt that is wound around these pulleys; and a first one-way clutch that is interposed between the rotating shaft and the first electric motor-generator pulley so as to transmit a rotational driving force from the crank shaft to the rotating shaft without transmitting a rotational driving force from the rotating shaft to the crank shaft, and the electric motor-generator is motor driven while the engine is being driven.