Even in the case where an additional heat exchanger must be arranged at the downstream side in the air flow direction of a multiple heat exchanger, a high flow-rate of air can be supplied to the additional heat exchanger arranged at the downstream side. In a state in which a reinforcement plate 3d of an outdoor heat exchanger 3 and a reinforcement plate 2d of a first radiator 2 come next to and overlap each other in series in the cooling air flow direction, both the reinforcement plates 2d and 3d are joined with a bolt 5. Due to this, a distance h between a first heat exchange core 2c and a second heat exchange core 3c is reduced. Therefore, air for cooling can be supplied, at a high flow-rate, to a second radiator 3 arranged at the downstream side.