By inserting an insertion section provided on a lower end of a motor fan unit into a wedge shaped hole provided in a lower part of a radiator, a motor fan unit is attached to a side of the radiator to the vehicle rear. A vehicle front perpendicular surface and a vehicle rear perpendicular surface are formed on the insertion section. The vehicle front perpendicular surface contacts a perpendicular surface of the wedge shaped hole, while the vehicle rear perpendicular surface contacts a lower end of an inclined surface of the wedge shaped hole. These surfaces will be in contact with one another even if the radiator stretches in the vertical direction due to evacuation and irrigation so that the insertion section slides upwards. As a result, it is possible to prevent rattling of the motor fan unit.