There are provided an electric motor (12) driven by an engine (8) to generate power or assists in driving the engine (8), a heat exchanger (13) to which cooling air is supplied by a cooling fan (8A), a heat exchanger upstream room (28) upstream of the heat exchanger (13), an electricity storage device (30) that stores or discharges power, and an inverter device (34) for controlling an operation of the electric motor (12). A radiator (42) for cooling the electricity storage device and a radiator (46) for cooling the are separately provided to be independent from each other, and are arranged in parallel between the heat exchanger (13) and the electricity storage device (30) in the heat exchanger upstream room (28).