Abstract: Disclosed is a heat insulating structure in which the surrounding of a heat insulating material such as glass wool is covered with and glued to a casing material such as a poly-film, wherein hotmelts (4,5,6) are applied to the center part or all and an inner portion d and an outer portion e of both ends of a poly-film (3b), and a glass wool (2) is placed on the center to apply a hotmelt (7) to the surface, which is then covered with an aluminum deposition poly-film. In the lower reaches of the conveyer, both ends of the lower poly-film (3b) are folded at the divided line between the inner portion d and the outer portion e to form a three-ply structure, which is pressed to fix, is cooled to normal temperature, and is cured. This heat insulating structure is featured in that improvement in productivity and high adhesive strength can be attained.