An air-conditioning apparatus includes an outdoor unit, an indoor unit having an indoor heat exchanger, and a controller for executing a pump down operation. The outdoor unit has an accumulator of a capacity (Va), a compressor, an outdoor heat exchanger, an expansion valve, a large-diameter tube, which are joined by refrigerant pipes. The capacity (Vhi) of the indoor heat exchanger is greater than the capacity (Vho) of the outdoor heat exchanger. The large-diameter tube, which is larger in diameter than the refrigerant pipes, is provided so that the capacity (Vt) of the large-diameter tube satisfies the formula: capacity (Vt)>capacity (Vhi)−capacity (Vho)−capacity (Va).