Abstract: A low-temperature showcase comprises a heat insulated wall, on the top of which an opening for putting-into or taking-out commodities is formed. The inside of the heat insulated wall is divided into an air passage and a storage chamber thereover by a dividing plate which is installed inside this heat insulated wall in a nearly horizontal fashion. The air passage is formed in a manner that the cross-section thereof is of a U-shape, and the storage chamber is formed surrounded by this air passage. At both ends of the air passage, vent ports are formed at the positions facing each other through the opening of the heat insulated wall inbetween. The air passage is divided into two parts by a fan case corresponding to the respective vent ports and a blast fan which can rotate reversibly is supported by this fan case. In each halved air passage, an evaporator is installed in the vicinity of the vent port, and when one of the evaporators is put in cooling operation, the other evaporator is subjected to defrosting.