An air conditioner is provided that may include an indoor device and an outdoor device. The outdoor device may include at least one compressor, an outdoor heat exchanger, a supercooling device that supercools a refrigerant, a first refrigerant pipe that allows the supercooling device to communicate with a suction side of the compressor, a first valve disposed in or on the first refrigerant pipe, a second refrigerant pipe that connects the compressor to the first refrigerant pipe, and at least one second valve disposed in or on the second refrigerant pipe. In a first refrigerant flow mode, a refrigerant flowing into the supercooling device may be introduced into the at least one compressor through the second refrigerant pipe. In a second refrigerant flow mode, a refrigerant compressed by the at least one compressor may be discharged into the second refrigerant pipe.