Resin coated can with folded seam

A retortable structure comprising a cylindrical body and a resin layer formed on the outside thereof, said cylindrical body serving as a content protecting layer which is formed by spirally wrapping a lmainate film composed of a polyolefin layer, a gas barrier layer, and a plastic layer around a mandrel, with one side edge thereof folded back and outward and the folded part bonded such that air bubbles are not entrapped thereunder, simultaneously superimposing the other side edge of the laminate film on the folded part and bonding them together such that air bubbles are not entrapped between them, said resin layer having sufficient thickness and strength such that said resin layer alone rigidifies the body to be self supporting, said resin layer being formed by melt extrusion onto the outside of said cylindrical body, with said cylindrical body cooled with water passing through the gap between the cylindrical body being formed and the mandrel, said resin layer being surface-finished by a smoothing means after melt extrusion and thereby lacking seams or bends.