HEAT EXCHANGER AND COOLING APPARATUS

PROBLEM TO BE SOLVED: To solve the problem with a prior art heat exchanger that heat exchange efficiency between a heat medium and the outside is bad. SOLUTION: A heat exchanger is adapted to comprise: pairs of header pipes of one set or a plurality of sets disposed in parallel; a plurality of heat transfer pipes 42, which have a through-hole penetrating lengthwise thereof through which a heat medium flows, and which are disposed in the thickness direction thereof at a predetermined interval, and further longitudinal opposite ends of which are connected to the pairs of the header pipes; and a plurality of fins 6 inserted between the disposed heat transfer pipes 42. In the heat exchanger, heat transfer resistance between the heat transfer pipes 42c, 42d, where the lengths of flow passages through which a heat medium flows among the heat transfer pipes 42 disposed in an adjacent relation are substantially different from each other, and larger than those between the adjacent heat transfer pipes 42 other than the foregoing heat transfer pipes.