PURPOSE: To eliminate, when a door is opened, decreases in cold insulation performance of an air curtain covering an opening of a case to be formed by a circulating flow in a vent passage while cooling the case having heat insulation by a refrigerator to be displayed and developed with a commodity therein by covering the opening opened at one surface of an outer periphery, cooling performance and a refrigerating efficiency of a display case.

CONSTITUTION: The display case comprises a refrigerator 16 having a ventilator 17 rotatably driven by a motor 17b to supply the air into a vent passage 5, an evaporator 11 for cooling the air flowing in the passage 5 as constituents. Number of revolutions of an impeller 17c of the ventilator 17 is varied at the times of opening and closing a door at an air flow rate of a circulating flow 13 flowing in the passage 5 by altering the number of revolutions of a rotor 17a of the motor 17b for rotatably driving the impeller 17c to prevent, when the door is opened, decreases in cold insulation performance of an air curtain 14, cooling performance and refrigerating efficiency of the display case.