An air-conditioning apparatus comprising: at least two outdoor units on each of which a compressor and an outdoor heat exchanger are mounted; and at least one indoor unit on which an indoor expansion device and an indoor heat exchanger are mounted, the outdoor units being connected to the indoor unit in parallel, the compressor , the indoor heat exchanger , the indoor expansion device , and the outdoor heat exchanger being sequentially connected by pipes and constituting a refrigerant circuit in which refrigerant is circulated, the outdoor unit including a hot-gas bypass pipe for bypassing discharging refrigerant from the compressor to the outdoor heat exchanger ; a first expansion device configured to regulate a flow rate of the refrigerant flowing through the hot-gas bypass pipe ; a liquid bypass pipe branching from a connection pipe for connecting the indoor unit and the outdoor heat exchanger and connected to a suction side of the compressor ; a second expansion device configured to regulate a flow rate of the refrigerant flowing through the liquid bypass pipe ; characterized in that the air-conditioning apparatus further comprises a third expansion device configured to regulate a flow rate of the refrigerant flowing through an outdoor-side connection pipe arranged on a side of the outdoor heat exchanger with respect to a branch point from the liquid bypass pipe in the connection pipe, and a controller configured to control the at least one outdoor unit to perform a defrosting operation in which the first expansion device is opened, the discharging refrigerant from the compressor is bypassed to the outdoor heat exchanger through the hot-gas bypass pipe , the third expansion device is closed, and an opening degree of the second expansion device is regulated when the other outdoor units are performing a heating operation. at least two outdoor units on each of which a compressor and an outdoor heat exchanger are mounted; and at least one indoor unit on which an indoor expansion device and an indoor heat exchanger are mounted, the outdoor units being connected to the indoor unit in parallel, the compressor , the indoor heat exchanger , the indoor expansion device , and the outdoor heat exchanger being sequentially connected by pipes and constituting a refrigerant circuit in which refrigerant is circulated, the outdoor unit including a hot-gas bypass pipe for bypassing discharging refrigerant from the compressor to the outdoor heat exchanger ; a first expansion device configured to regulate a flow rate of the refrigerant flowing through the hot-gas bypass pipe ; a liquid bypass pipe branching from a connection pipe for connecting the indoor unit and the outdoor heat exchanger and connected to a suction side of the compressor ; a second expansion device configured to regulate a flow rate of the refrigerant flowing through the liquid bypass pipe ; characterized in that the air-conditioning apparatus further comprises a third expansion device configured to regulate a flow rate of the refrigerant flowing through an outdoor-side connection pipe arranged on a side of the outdoor heat exchanger with respect to a branch point from the liquid bypass pipe in the connection pipe, and a controller configured to control the at least one outdoor unit to perform a defrosting operation in which the first expansion device is opened, the discharging refrigerant from the compressor is bypassed to the outdoor heat exchanger through the hot-gas bypass pipe , the third expansion device is closed, and an opening degree of the second expansion device is regulated when the other outdoor units are performing a heating operation. <EOS>