Abstract: The air conditioner includes: an outdoor unit that includes a compressor, an outdoor heat exchanger, and an outdoor expansion valve; an indoor unit that includes an indoor heat exchanger and an indoor expansion valve; a liquid pipe that connects the outdoor unit to the indoor unit; and a gas pipe that connects the outdoor unit to the indoor unit. One end of the outdoor heat exchanger is coupled to the liquid pipe through the outdoor expansion valve. One end of the indoor heat exchanger is coupled to the liquid pipe through the indoor expansion valve. When a predetermined period of time elapses after the compressor is shut down, the outdoor expansion valve and the indoor expansion valve both close.