A cooling cycle apparatus for a refrigerator includes a first compressor, a condenser for condensing a refrigerant compressed in the first compressor, a first expansion device for lowering a temperature and a pressure of a portion of the condensed refrigerant, a first evaporator for evaporating the refrigerant, a second expansion device for lowering a temperature and a pressure of a remaining portion of the refrigerant, a gas-liquid separator for separating a liquid-phase refrigerant from a gas-phase refrigerant in the refrigerant, a third expansion device for lowering a temperature and a pressure of the liquid-phase refrigerant, 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.