PURPOSE: To keep in-store environment comfortable by removing humidity in a store with open showcases as well as from the floor surface of cold aisles, decrease the amount of frost to be formed on the showcases by removing humidity in the store, thereby reducing the number of defrosting operations, maintain freshness of foodstuffs and reduce the cost of freezing and refrigerating equipment.

CONSTITUTION: A suction port 1b for air cooled by an air curtain and stayed in front of an open showcase 1 is provided at the base part of the showcase 1, and a suction duct 3 communicating with the suction port 1b is connected to a main body 4 of an air conditioner. A cooling coil 4b disposed in the main body of the air conditioner is connected to a freezer 7 for the air conditioner through a pipeline 9 with a solenoid valve 10, and a heating coil 4d is also connected to a refrigerant outlet pipe of a freezer 8 for the showcase through a pipeline 12 with a three-way valve 13. Both the valves are controlled by a control panel 11 which detects a temperature and humidity in a store to control the opening and closing of the valves, whereby a temperature and humidity of air which passes through the main body of the air conditioner to contact with the cooling and heating coils are controlled, and cold air is blown by an blower 4e from a ceiling part into the store.