A plurality of heat transfer pipes have a circumferential portion arranged at a short distance from an inner surface of a heat exchanger case while they are bundled to form a pipe group and a first chord which retracts toward a center in a direction of cylinder diameter from an arc formed by the circumferential portion. The plurality of bundled heat transfer pipes are loaded in the exchange case such that the first chord and an inner surface of the heat exchange case on a side where a heat exchange medium inlet port is attached are opposed to each other. By making a flow of a heat exchange medium to each heat transfer pipe uniform, a heat exchanger capable of obtaining high heat exchange performance is obtained.
