A heat exchanger for an air conditioner, for connecting a compressor (COMP) for compressing refrigerant to an expansion device for expanding condensed refrigerant via a piping and for receiving low temperature/pressure refrigerant coming from the expansion device during a cooling mode, the heat exchanger comprising: at least one refrigerant inlet (111,211) in terms of cooling mode for receiving refrigerant; a plurality of refrigerant outlets (131,231) in terms of cooling mode for discharging the refrigerant; at least one inlet heat exchanging part (110,210) having the at least one refrigerant inlet (111,211); at least one branch pipe (120;220) for distributing the refrigerant during a cooling operation mode and for concentrating the refrigerant during a heating operation mode, each of the at least one refrigerant inlet (111,211) of each of the at least one inlet heat exchanging part (110,210) being connected to one branch pipe (120;220); and a plurality of branched heat exchanging parts (130,230), each one end thereof connected to one end of the at least one branch pipe (120;220) and each other end thereof formed with the refrigerant outlet (131,231), wherein the number of the refrigerant outlets (131,231) is greater than that of the at least one refrigerant inlet (111,211), characterized in that the heat exchanger comprises: a first heat exchanging part; and a second heat exchanging part, each part comprising: a singular inlet heat exchanging part (110,210), a singular branch pipe (120,220) and two branched heat exchanging parts (130,230), wherein a refrigerant inlet of the first heat exchanging part and a refrigerant inlet of the second heat exchanging part are connected to the expansion device, and a refrigerant outlet of the first heat exchanging part and a refrigerant outlet of the second heat exchanging part are connected to the compressor (COMP). at least one refrigerant inlet (111,211) in terms of cooling mode for receiving refrigerant; a plurality of refrigerant outlets (131,231) in terms of cooling mode for discharging the refrigerant; at least one inlet heat exchanging part (110,210) having the at least one refrigerant inlet (111,211); at least one branch pipe (120;220) for distributing the refrigerant during a cooling operation mode and for concentrating the refrigerant during a heating operation mode, each of the at least one refrigerant inlet (111,211) of each of the at least one inlet heat exchanging part (110,210) being connected to one branch pipe (120;220); and a plurality of branched heat exchanging parts (130,230), each one end thereof connected to one end of the at least one branch pipe (120;220) and each other end thereof formed with the refrigerant outlet (131,231), wherein the number of the refrigerant outlets (131,231) is greater than that of the at least one refrigerant inlet (111,211), characterized in that the heat exchanger comprises: a first heat exchanging part; and a second heat exchanging part, each part comprising: a singular inlet heat exchanging part (110,210), a singular branch pipe (120,220) and two branched heat exchanging parts (130,230), a first heat exchanging part; and a second heat exchanging part, each part comprising: a singular inlet heat exchanging part (110,210), a singular branch pipe (120,220) and two branched heat exchanging parts (130,230), wherein a refrigerant inlet of the first heat exchanging part and a refrigerant inlet of the second heat exchanging part are connected to the expansion device, and a refrigerant outlet of the first heat exchanging part and a refrigerant outlet of the second heat exchanging part are connected to the compressor (COMP).