An air conditioner is provided, in which some of a plurality of outdoor heat exchangers implement a defrosting operation and others implement a heating operation. The air conditioner includes a compressor to compress refrigerant, a hot gas pipe to which a part of the refrigerant compressed in the compressor is moved, a 4-way valve to which the remaining refrigerant compressed in the compressor is moved, an indoor heat exchanger in which the refrigerant, having passed through the 4-way valve, undergoes heat exchange with indoor air, and a plurality of outdoor heat exchangers, some of which implement a heating operation as the heat-exchanged refrigerant from the indoor heat exchanger is moved therethrough while others implement a defrosting operation as the refrigerant having passed through the hot gas pipe is moved therethrough.