A cooling cycle apparatus for a refrigerator, comprising: a first compressor for compressing a refrigerant; a condenser for condensing the refrigerant compressed in the first compressor; a first expansion device for lowering a temperature and a pressure of a portion of the refrigerant condensed in the condenser; a first evaporator for evaporating the refrigerant that has passed through the first expansion device; a second expansion device for lowering a temperature and a pressure of a remaining portion of the refrigerant condensed in the condenser; a gas-liquid separator for separating a liquid-phase refrigerant from a gas-phase refrigerant in the refrigerant that has passed through the second expansion device; a third expansion device for lowering a temperature and a pressure of the liquid-phase refrigerant separated in the gas-liquid separator; a second evaporator for evaporating the refrigerant that has passed through the third expansion device; and a second compressor for compressing the refrigerant that has passed through the second evaporator and transferring the refrigerant to the first compressor, wherein the refrigerant that has passed through the first evaporator and the gas-phase refrigerant separated in the gas-liquid separator are introduced into the first compressor together with the refrigerant compressed in the second compressor, characterized in that the refrigerator further comprises a heat exchanging unit, which is provided downstream of the condenser so as to exchange heat between the gas-phase refrigerant that has passed through the gas-liquid separator and the refrigerant condensed in the condenser. a first compressor for compressing a refrigerant; a condenser for condensing the refrigerant compressed in the first compressor; a first expansion device for lowering a temperature and a pressure of a portion of the refrigerant condensed in the condenser; a first evaporator for evaporating the refrigerant that has passed through the first expansion device; a second expansion device for lowering a temperature and a pressure of a remaining portion of the refrigerant condensed in the condenser; a gas-liquid separator for separating a liquid-phase refrigerant from a gas-phase refrigerant in the refrigerant that has passed through the second expansion device; a third expansion device for lowering a temperature and a pressure of the liquid-phase refrigerant separated in the gas-liquid separator; a second evaporator for evaporating the refrigerant that has passed through the third expansion device; and a second compressor for compressing the refrigerant that has passed through the second evaporator and transferring the refrigerant to the first compressor, wherein the refrigerant that has passed through the first evaporator and the gas-phase refrigerant separated in the gas-liquid separator are introduced into the first compressor together with the refrigerant compressed in the second compressor, characterized in that the refrigerator further comprises a heat exchanging unit, which is provided downstream of the condenser so as to exchange heat between the gas-phase refrigerant that has passed through the gas-liquid separator and the refrigerant condensed in the condenser.