To improve cooling efficiency and to save power consumption by adjusting the speed controlling signal of a blower at predetermined intervals repeatedly for regulating the rotational speed of the blower according to the current temperature of an evaporator and driving the blower based on the latest speed control signal being adjusted.

The evaporation temperature sensing part 230 sensing the temperature of the evaporator 70 of a refrigerator transmits the sensed temperature signal to a control part 240. Comparing by the control part 240 between the inside temperature of the refrigerator set by a user through a temperature setting part 210 and the current inside temperature of the refrigerator sensed by an inside refrigerator temperature sensing part 220, driving signals for driving a compressor 120 based on the result of comparison are generated and applied to a compressor driving part 250. Pulse width modulation signals of predetermined duty ratio for driving the blower based on the result of the comparison is applied to the blower driving part 260 and the duty ratio of the pulse width modulation signals is adjusted according to the temperature of the evaporator and the rotational speed of the blower.