A refrigerator a duct arranged to partition an inner space of a storage chamber body into a storage chamber and an air flow channel, wherein the duct has an ejection hole defined therein; a roll-bond evaporator disposed in the air flow channel, wherein the roll-bond evaporator has a top and a bottom, a left end and a right end; a blowing fan configured to draw air from the storage chamber to blow the air into the air flow channel; and a defrost sensor closer to one of the top and bottom than the other of the top and the bottom, wherein said one is closer to the blowing fan than the other, wherein the sensor is closer to one of the left end and the right end than the other of the left end and the right end.