PROBLEM TO BE SOLVED: To provide a disposable diaper preventing frill from being formed at side areas in a crotch part, having underwear-like external appearance and having the side areas with favorable texture.SOLUTION: Width-directional side areas 1Cs in a crotch part 1C comprise a laminated structure of a plurality of sheets 31 and 32. A side edge 1Ct extending in the longitudinal direction X in each width-directional side area 1Cs comprises a fusion part 40 formed by fusing the plurality of sheets. In a spread and stretched state of the diaper, an elastic member 7 extending in the longitudinal direction is disposed at a position some distance spaced inward in the width direction Y from the side edge 1Ct in the width-direction side area 1Cs. The disposable diaper further includes a non-joined part where the two sheets 31 and 32 adjacent to the elastic member 7 in the width direction are not joined, formed between the side edge 1Ct and the elastic member 7 in the plane direction crossing with the side edge 1Ct.
