A water-cooled air conditioner, the water-cooled air conditioner comprising: a first heat exchanger indoor air is heat-exchanged with refrigerant; a compressor for compressing the refrigerant; an accumulator that is installed at a side of the compressor to filter off liquid-phase refrigerant so that only gas-phase refrigerant can be introduced into the compressor; and a plate-shaped second heat exchanger the refrigerant is heat-exchanged with the water, characterized in that the water-cooled air conditioner further comprises a refrigerant bypassing unit selectively operates to allow a portion of the refrigerant compressed in the compressor to be directly returned to the second heat exchanger, the refrigerant bypassing unit comprising: a hot gas pipe that is disposed between the compressor and the accumulator to allow the high pressure refrigerant discharged from the compressor to be returned to the accumulator; and a refrigerant bypassing pipe for guiding a refrigerant flow direction, the refrigerant bypassing pipe has first end connected to a side of the hot gas pipe and second end connected to a refrigerant inlet of the second heat exchanger, wherein when the refrigerant bypassing unit operates, a portion of the refrigerant discharged from the compressor is directed to the first heat exchanger, and the rest of the refrigerant is introduced into the second heat exchanger along the hot gas pipe and the refrigerant bypassing pipe, and wherein the refrigerant bypassing unit selectively operates depending on a temperature of the water passing through the plate-shaped second heat exchanger when the air conditioner operates in a heat mode, wherein the refrigerant bypassing unit comprises a bypassing blocking valve for selectively blocking the refrigerant bypassing pipe. a first heat exchanger indoor air is heat-exchanged with refrigerant; a compressor for compressing the refrigerant; an accumulator that is installed at a side of the compressor to filter off liquid-phase refrigerant so that only gas-phase refrigerant can be introduced into the compressor; and a plate-shaped second heat exchanger the refrigerant is heat-exchanged with the water, characterized in that the water-cooled air conditioner further comprises a refrigerant bypassing unit selectively operates to allow a portion of the refrigerant compressed in the compressor to be directly returned to the second heat exchanger, the refrigerant bypassing unit comprising: a hot gas pipe that is disposed between the compressor and the accumulator to allow the high pressure refrigerant discharged from the compressor to be returned to the accumulator; and a refrigerant bypassing pipe for guiding a refrigerant flow direction, the refrigerant bypassing pipe has first end connected to a side of the hot gas pipe and second end connected to a refrigerant inlet of the second heat exchanger, a hot gas pipe that is disposed between the compressor and the accumulator to allow the high pressure refrigerant discharged from the compressor to be returned to the accumulator; and a refrigerant bypassing pipe for guiding a refrigerant flow direction, the refrigerant bypassing pipe has first end connected to a side of the hot gas pipe and second end connected to a refrigerant inlet of the second heat exchanger, wherein when the refrigerant bypassing unit operates, a portion of the refrigerant discharged from the compressor is directed to the first heat exchanger, and the rest of the refrigerant is introduced into the second heat exchanger along the hot gas pipe and the refrigerant bypassing pipe, and wherein the refrigerant bypassing unit selectively operates depending on a temperature of the water passing through the plate-shaped second heat exchanger when the air conditioner operates in a heat mode, wherein the refrigerant bypassing unit comprises a bypassing blocking valve for selectively blocking the refrigerant bypassing pipe.