A heat exchanger shunt comprising: a plurality of flat pipes having a plurality of refrigerant flow paths; and a pair of header pipes (3a, 3b) each of which connects both ends of the flat pipes, wherein the header pipes each include a partition plate (9a, 9b, 9c) which divides the plurality of flat pipes into a plurality of heat exchange sections (8a, 8b, 8c, 8d), a first refrigerant piping is provided to an upper portion of one header pipe of the header pipes, while a second refrigerant piping is provided to a lower portion of the one header pipe so that refrigerant outflows from the first refrigerant piping into the second refrigerant piping when the heat exchanger functions as an evaporator, the other header pipe of the header pipes includes a partition wall which divides a connection-side space of the flat pipes and a non-connection-side space of the flat pipes in a refrigerant outflow section from which the refrigerant outflows to the plurality of flat pipes, the partition wall includes a plurality of communication holes (16a, 16b), which is arranged in a vertical direction and which is arranged in use at an upper side of an intermediate position of the refrigerant outflow section in the vertical direction, and one communication hole of the communication holes has a larger opening area than an opening area of another communication hole of the communication holes, which is in use immediately below the one communication hole characterized in that in the non-connection-side space, a flow adjustment portion having a rising slope is provided, the rising slope being in use from a wall surface of the header pipe to the partition wall at an upper end of the communication hole existing at an uppermost stage of the plurality of communication holes. a plurality of flat pipes having a plurality of refrigerant flow paths; and a pair of header pipes (3a, 3b) each of which connects both ends of the flat pipes, wherein the header pipes each include a partition plate (9a, 9b, 9c) which divides the plurality of flat pipes into a plurality of heat exchange sections (8a, 8b, 8c, 8d), a first refrigerant piping is provided to an upper portion of one header pipe of the header pipes, while a second refrigerant piping is provided to a lower portion of the one header pipe so that refrigerant outflows from the first refrigerant piping into the second refrigerant piping when the heat exchanger functions as an evaporator, the other header pipe of the header pipes includes a partition wall which divides a connection-side space of the flat pipes and a non-connection-side space of the flat pipes in a refrigerant outflow section from which the refrigerant outflows to the plurality of flat pipes, the partition wall includes a plurality of communication holes (16a, 16b), which is arranged in a vertical direction and which is arranged in use at an upper side of an intermediate position of the refrigerant outflow section in the vertical direction, and one communication hole of the communication holes has a larger opening area than an opening area of another communication hole of the communication holes, which is in use immediately below the one communication hole characterized in that in the non-connection-side space, a flow adjustment portion having a rising slope is provided, the rising slope being in use from a wall surface of the header pipe to the partition wall at an upper end of the communication hole existing at an uppermost stage of the plurality of communication holes.