An air conditioner includes a bypass pipe connecting a first bypass branch of a first connection pipe, through which high-pressure refrigerant flows, with a second bypass branch of a third connection pipe, through which low-pressure refrigerant flows, to allow bypassing of high-pressure refrigerant in the first connection pipe to the third connection pipe, and a bypass valve mounted in the bypass pipe. During a cooling operation of an indoor unit, the bypass valve is opened to allow bypassing of high-pressure refrigerant of the first connection pipe to the third connection pipe.