Abstract: A complex heat exchanger (1) according to the present invention includes a sub radiator (20) for cooling water-cooling cooling water passing through heavy current device (3), an air-cooled condenser (40) for cooling a air-conditioning refrigerant different from the water-cooling cooling water, and a water-cooled condenser (30) for performing heat exchange between the water-cooling cooling water and the air-conditioning refrigerant. The water-cooling cooling water flows into the sub radiator (20) after passing through the water-cooled condenser (30) and is cooled and then, the water-cooling cooling water is used for cooling of the heavy current device (3). The air-conditioning refrigerant cooled by the water-cooled condenser (30) flows into the air-cooled condenser (40).