Heat exchanger and air conditioning device

A heat exchanger includes a plurality of flat tubes, a header collecting tube, and fins joined to the flat tubes. The header collecting tube includes a first partition member partitioning an internal space into upper and lower internal spaces, a second partition member partitioning the upper internal space into first and second spaces, an inflow port formed on the first partition member at a bottom part of the first space so as to penetrate in a plate thickness direction, an upper communicating passage, a lower communicating passage. The flat tubes are connected at one end to the first space of the header collecting tube. An inflow pipeline is connected to space that, within the lower internal space, is underneath the second space.