An air conditioner comprising a compressor configured to compress a refrigerant, a condenser configured to condense the compressed refrigerant, an additional heat exchanger, such as a super cooling device (100, 200), configured to heat exchange with, in particular to super-cool, the refrigerant after the refrigerant passes through the condenser, and an evaporator configured to evaporate the refrigerant after the refrigerant passes through the additional heat exchanger, such as the super cooling device (100, 200), wherein the additional heat exchanger, such as the super cooling device (100, 200), comprises: a first flow passage (141, 271) disposed in the additional heat exchanger, such as the super cooling device (100, 200), to guide the refrigerant coming from the condenser toward the evaporator; a second flow passage (142, 272) located in the additional heat exchanger, such as the super cooling device (100, 200), for exchanging heat with the first flow passage (141, 271) and guiding the refrigerant toward the compressor; wherein one of the first (141, 271) and second (142, 272) flow passage comprises a distribution part (120, 220) configured to divide a flow of the refrigerant and a plurality of inner tubes connected to the distribution part (120, 220), characterised in that a third flow passage is located in the additional heat exchanger, such as the super cooling device (100, 200), for exchanging heat with the first flow passage (141,271) and guiding the refrigerant passing through the evaporator toward the compressor, and in that the additional heat exchanger further comprises a main body (110, 210) comprising a first main body having a first heat exchange region in which the first (141, 271) and second (142, 272) flow passages are disposed, a second main body having a second heat exchange region in which the first (141, 271) and third flow passages are disposed and a partition part (225, 240) disposed between the first main body and the second main body, and in that the refrigerant in the first flow passage (141, 271) flows sequentially in the first and the second main bodies to exchange heat with the refrigerant in the second (142, 272) and third flow passages. a first flow passage (141, 271) disposed in the additional heat exchanger, such as the super cooling device (100, 200), to guide the refrigerant coming from the condenser toward the evaporator; a second flow passage (142, 272) located in the additional heat exchanger, such as the super cooling device (100, 200), for exchanging heat with the first flow passage (141, 271) and guiding the refrigerant toward the compressor; wherein one of the first (141, 271) and second (142, 272) flow passage comprises a distribution part (120, 220) configured to divide a flow of the refrigerant and a plurality of inner tubes connected to the distribution part (120, 220), characterised in that a third flow passage is located in the additional heat exchanger, such as the super cooling device (100, 200), for exchanging heat with the first flow passage (141,271) and guiding the refrigerant passing through the evaporator toward the compressor, and in that the additional heat exchanger further comprises a main body (110, 210) comprising a first main body having a first heat exchange region in which the first (141, 271) and second (142, 272) flow passages are disposed, a second main body having a second heat exchange region in which the first (141, 271) and third flow passages are disposed and a partition part (225, 240) disposed between the first main body and the second main body, and in that the refrigerant in the first flow passage (141, 271) flows sequentially in the first and the second main bodies to exchange heat with the refrigerant in the second (142, 272) and third flow passages.