[Object] To provide an air-conditioning-apparatus outdoor unit including a socket that can be used in cold climate areas.[Solution] An outdoor unit 100 includes a base plate 12 having a hole 13 and a socket 50 attached to the base plate 12 with a clearance 16 provided between the socket 50 and a lower surface of the base plate 12, the socket 50 communicating with the hole 13 to provide a first drainage path. The clearance 16 functions as a second drainage path for allowing drain water from the hole 13 to be guided out of the outdoor unit 100 when the first drainage path is blocked.