PURPOSE: To provide a cooled storage chamber that maintains the temperature of a refrigerating chamber by fuzzy inference and is able to keep received refrigerating foods from thawing.

CONSTITUTION: The difference DV between the refrigerating chamber temperature TF and the upper limit temperature, -10°C and the variation DTF of the temperature TF are measured by a refrigeration chamber temperature sensor 48. A microcomputer 46 seeks an output Y that determines the degree OP of opening of an electromotive damper by fuzzy inference which employs DV as a first input variable X1 and DTF as a second input variable X2 and regulates the volume of supplied cold air to a cold storage chamber.