a refrigerator with heat exchanger optimally configured to conserve electricity and improve a food storing capability at its best state . the refrigerator includes : a freezing room connected from an evaporator through a circulating passage , the freezing room having the circulating passage which circulates an air cooled by the evaporator ; a storage room connected to the freezing room , in which a temperature of the storage room is set higher than that of the freezing room ; a flow - in passage connected to the storage room where the air cooled by the evaporator flows into the storage room ; a flow - out passage connected from the storage room where a chilled air flows out of the storage room ; and a heat exchanger for exchanging heat between the cooled air flowing through the circulating passage and the chilled air flowing through the flow - out passage , so that the temperature inside the storage room is evenly and smoothly stable .