High-tension cables 7U, 7V, 7W connect an inverter 6 disposed outside an engine compartment with a motor/generator 3 disposed in the engine compartment, the high-tension cables 7U, 7V, 7W are individually passed through metallic protection pipes 30 under a floor of a vehicle, the protection pipes 30 are supported from an underside of the floor, and the high-tension cables 7U, 7V, 7W are passed through a protection tube 20 over a predetermined distance from the motor/generator 3 in the engine compartment.