A heat insulation container includes an inner casing, an outer casing on the exterior thereof and enclosing the inner casing and defining a space therebetween in cooperation with the inner casing, and a heat insulating foamed material filling the space defined by the casings. An aperture portion is provided in the container through a wall thereof for allowing a piping of a cooling system to go in and out of the container therethrough. The aperture portion is provided with a frame therearound which comprises an annular resilient contacting member brought into hermetical sealing contact with the inner surface of either the inner casing or the outer casing in the vicinity of a periphral edge of the mouth, and an annular tong-like member engaging sealingly with the other of the inner casing and the outer casing.