There is provided a heat exchanger including: a heat exchange section in which a plurality of flat tubes are arranged substantially in parallel in a minor axis direction at first intervals and in which fins are disposed between the flat tubes; and a header to which at least some flat tubes out of the plurality of flat tubes are connected, in a state where the at least some flat tubes are bent in the minor axis direction outside the heat exchange section and end parts of the at least some flat tubes are arranged substantially in parallel at second intervals that are narrower than in the heat exchange section, so that the minor axis direction and a central axis direction of the header are the same direction. With this heat exchanger, it is possible to distribute fluid to the individual flat tubes with more equal conditions so that the heat exchange efficiency can be increased.