A refrigerator comprising: a refrigerator main body having at least one chamber (2, 3) and at least one door (4, 5) for opening/closing the at least one chamber (2, 3), and having at least one ice making tray; a compressor disposed in the refrigerator main body; a condenser disposed in the refrigerator main body and connected to the compressor; a cooling evaporator disposed in the refrigerator main body and connected to the condenser for supplying cold air into the at least one chamber (2, 3); and an ice making evaporator disposed in the refrigerator main body and connected to the condenser for freezing water contained in the ice making tray, characterised in that the ice making evaporator further comprises a housing having an inlet and an outlet allowing introduction and discharge of a refrigerant, and at least one or more ice core portions each protruding from one side of the housing by a certain length and being sunk in the water of the ice making tray, and in that the refrigerator further comprises: a water tank configured to store water to be supplied into the ice making tray or water recollected from the ice making tray; a water supply/drain line connected between the water tank and the ice making tray; and a water pump configured so as to alternately supply or drain the water, and disposed in a portion of the water supply/drain line and configured to pump water of the water tank so as to supply water to the ice making tray via the water supply/drain line for making ice at the at least one ice core portion and pump water remaining in the ice making tray so as to drain into the water tank via the water supply/drain line before ice made at the at least one ice core portion is separated. a refrigerator main body having at least one chamber (2, 3) and at least one door (4, 5) for opening/closing the at least one chamber (2, 3), and having at least one ice making tray; a compressor disposed in the refrigerator main body; a condenser disposed in the refrigerator main body and connected to the compressor; a cooling evaporator disposed in the refrigerator main body and connected to the condenser for supplying cold air into the at least one chamber (2, 3); and an ice making evaporator disposed in the refrigerator main body and connected to the condenser for freezing water contained in the ice making tray, characterised in that the ice making evaporator further comprises a housing having an inlet and an outlet allowing introduction and discharge of a refrigerant, and at least one or more ice core portions each protruding from one side of the housing by a certain length and being sunk in the water of the ice making tray, and in that the refrigerator further comprises: a water tank configured to store water to be supplied into the ice making tray or water recollected from the ice making tray; a water supply/drain line connected between the water tank and the ice making tray; and a water pump configured so as to alternately supply or drain the water, and disposed in a portion of the water supply/drain line and configured to pump water of the water tank so as to supply water to the ice making tray via the water supply/drain line for making ice at the at least one ice core portion and pump water remaining in the ice making tray so as to drain into the water tank via the water supply/drain line before ice made at the at least one ice core portion is separated. a water tank configured to store water to be supplied into the ice making tray or water recollected from the ice making tray; a water supply/drain line connected between the water tank and the ice making tray; and a water pump configured so as to alternately supply or drain the water, and disposed in a portion of the water supply/drain line and configured to pump water of the water tank so as to supply water to the ice making tray via the water supply/drain line for making ice at the at least one ice core portion and pump water remaining in the ice making tray so as to drain into the water tank via the water supply/drain line before ice made at the at least one ice core portion is separated.