Provided is a disposable diaper that protects the navel while suppressing irritation to the skin of a wearer and that can reduce stress on mothers concerning irritation to the skin. A front edge (11) of a disposable diaper (10) has a curve-shaped recessed part (111) that is recessed toward the rear side, in an area including the widthwise center of the disposable diaper, and front straight parts (112) extending from the outer edges of the recessed part so as to be parallel to the width direction, and a rear edge (12) of the disposable diaper has a curve-shaped projecting part (121) projecting toward the rear side, in an area including the widthwise center of the disposable diaper, and rear straight parts (122) extending from the outer edges of the projecting part so as to be parallel to the width direction. The disposable diaper has a pair of first cut-out parts (15), which are recessed, in a curved manner, from the outer edges of the front straight parts toward the rear side and are recessed, in a curved manner, from the front edges of the outer edges of the disposable diaper toward the widthwise inner side, and a pair of second cut-out parts (16), which are recessed, in a curved manner, from the outer edges of the rear straight parts toward the front side and are recessed, in a curved manner, from the rear edges of the outer edges of the disposable diaper toward the widthwise inner side.提供一種，邊抑制對穿用者的肌膚的刺激邊保護肚臍，並且，可減低母親對於朝肌膚的刺激的緊張情緒的用後即棄式紙尿布。用後即棄式紙尿布(10)的前端緣(11)具有：在包含用後即棄式紙尿布的寬邊方向中心的區域，朝向後方凹陷的曲線狀的凹部(111)、以及從凹部的外側緣相對於寬邊方向平行延伸的前直線部(112)，用後即棄式紙尿布的後端緣(12)具有：在包含用後即棄式紙尿布的寬邊方向中心的區域，朝向後方突出的曲線狀的凸部(121)、以及從凸部的外側緣相對於寬邊方向平行的後直線部(122)。用後即棄式紙尿布具有：從前直線部中的外側緣朝向後方曲線狀凹陷，且從用後即棄式紙尿布的外側緣中的前端緣朝向寬邊方向內側曲線狀凹陷的一對的第1缺口部(15)、以及從後直線部中的外側緣朝向前方曲線狀凹陷，且從用後即棄式紙尿布的外側緣中的後端緣朝向寬邊方向內側曲線狀凹陷的一對的第2缺口部(16)。
