PURPOSE: To perform an automatic shielding of a cold air passage and improve a communication of the cold air passage and a convenience in use of a refrigerator by a method wherein when a thermal insulating box device is fixed to a cooling device, a damper at an opening or closing port is pushed up with the thermal insulating box device to feed cold air and in turn when the thermal insulating box device is removed, the damper is lowered and means for closing a passage for cold air is provided.

CONSTITUTION: When a thermal insulating box All is connected to a cooling device 1, an upper piece 24 at one end 7 of a moving plate 10 is pushed up by a lower surface 25 of the thermal insulating box All. The other end 9 is raised around a central axis of a supporting point 6 and an opening 5 is opened. The other end 9 pushes up a damper 21 around a supporting point B20 and then a discharged cold air passage port 18 and a returning cold air passage port 19 are opened. Thus, an air passage connecting a cooling device 2 with a refrigerator 17 is completed. In addition, when the thermal insulating box All is separated from the cooling device 1, a force for the moving plate 10 is eliminated, the other end 9 closes an opening side 8a of an opening 5 around the supporting point 6 by its own weight. A lower end piece 26 at one end 7 is also abutted against the opening side 8 and then the opening 5 is closed. A force added from the other end 9 of the moving plate 10 is not applied to the damper 21, the other end 27 closes the discharged cold air passage port 18 and the return cold air passage port 19 around a central axis of the supporting point B20 by its own weight, respectively.