A retort cup comprising: a tubular barrel portion formed of a barrel portion forming blank having a paper layer and thermoplastic resin layers (40, 41) provided on both surfaces of the paper layer; and a bottom portion which seals one of the openings of the barrel portion, wherein the bottom portion has a downwardly bent peripheral edge portion, wherein the barrel portion has an attached barrel overlap portion where both end edges of the barrel portion forming blank are overlapped with each other and sealed, a lower fold-back portion which is formed at a lower end of the barrel portion by folding back the barrel portion forming blank inwardly, and an upper fold-back portion which is formed by folding back the ends of the fold-back barrel portion forming blank inwardly, wherein the lower end of the barrel portion, the upper fold-back portion, and the peripheral edge portion of the bottom portion are closely sealed together, with the peripheral edge portion of the bottom portion being inserted into the lower fold-back portion, characterised in that end edge extending portions (4a, 4c) are provided such that the thermoplastic resin layers extend over a predetermined width externally from the paper layer at both end edges of the barrel portion, the thermoplastic resin layers sealing each end surface (11, 12) of the paper layer, wherein at least one of the end edge extending portions is folded back and located between the end edges of the barrel portion, and wherein the end surface of the paper layer located inside the barrel overlap portion is protected by the fold-back resin portion of the end edge extending portion. a tubular barrel portion formed of a barrel portion forming blank having a paper layer and thermoplastic resin layers (40, 41) provided on both surfaces of the paper layer; and a bottom portion which seals one of the openings of the barrel portion, wherein the bottom portion has a downwardly bent peripheral edge portion, wherein the barrel portion has an attached barrel overlap portion where both end edges of the barrel portion forming blank are overlapped with each other and sealed, a lower fold-back portion which is formed at a lower end of the barrel portion by folding back the barrel portion forming blank inwardly, and an upper fold-back portion which is formed by folding back the ends of the fold-back barrel portion forming blank inwardly, wherein the lower end of the barrel portion, the upper fold-back portion, and the peripheral edge portion of the bottom portion are closely sealed together, with the peripheral edge portion of the bottom portion being inserted into the lower fold-back portion, characterised in that end edge extending portions (4a, 4c) are provided such that the thermoplastic resin layers extend over a predetermined width externally from the paper layer at both end edges of the barrel portion, the thermoplastic resin layers sealing each end surface (11, 12) of the paper layer, wherein at least one of the end edge extending portions is folded back and located between the end edges of the barrel portion, and wherein the end surface of the paper layer located inside the barrel overlap portion is protected by the fold-back resin portion of the end edge extending portion.