An air-conditioner outdoor heat exchanger has a fin, multiple heat transfer pipes thermally connected to the fin, having a flat sectional shape, and configured such that refrigerant flows through header pipes connected to inlet and outlet sides of the heat transfer pipes. The refrigerant flows through the heat transfer pipes in parallel, and when the refrigerant returns from the outlet-side header pipe to the inlet-side header pipe through the heat transfer pipes, the refrigerant returns to the inlet-side header pipe through one of the heat transfer pipes adjacent to another one of the heat transfer pipes through which the refrigerant has flowed when flowing from the inlet-side header pipe to the outlet-side header pipe. At least two systems of refrigerant paths are formed, and the refrigerant flows back and forth in each system between the inlet-side header pipe and the outlet-side header pipe.