To provide a low-temperature container where a rise of the internal temperature is gentle even if the cooling within a storage stops by power failure, etc. by lessening the temperature difference within the storage of the low- temperature container.

A low-temperature container is equipped with a storage 11 which accommodates within the substance to be cooled, being surrounded by an inner plate 9, a cooling coil 13 which circulates a refrigerant, being arranged outside this storage 11, a heat insulating material 15 which interrupts the penetration of heat from outside, covering the storage 11 and the cooling coil 13, and a casing 17 which surrounds this heat insulating material 15. This container is provided with a heat storage cap 23 to store cold and heat of the cooling coil 13, in contact with the cooling coil 13, outside the top of the storage 11.