A disposable diaper (10) has an absorbent core (40a) having wide sections and a narrow section wherein the length of the absorbent core in the width direction is shortest. Marker patterns (M11, M12), which indicate positions on the absorbent core, are attached to a back sheet positioned more on a non-skin-contact surface side than the absorbent core (40a). The marker patterns are disposed at positions that do not overlap with the outer edge of the absorbent core in a product width direction. At least a portion of each marker pattern in an overlapping region where the absorbent core and the back sheet overlap is disposed in a region further to the outside in the product width direction than an imaginary line (FL1), which passes through the outer edge of the narrow section in the product width direction and extends in a product longitudinal direction.用後即棄式紙尿布(1)係具備吸收性芯材(40a)，其具有寬度廣部、及吸收性芯材的寬度方向之長度最短的寬度窄部。在位於較吸收性芯材(40a)更靠近非肌膚抵接面側之背面薄片，被賦予有顯示吸收性芯材的位置之標示圖案(M11、M12)。標示圖案係配置在不會重疊於吸收性芯材的製品寬度方向外側端部之位置。標示圖案的至少一部分係設置在吸收性芯材與背面薄片重疊的重疊區域中，較通過寬度窄部的製品寬度方向外側端部且朝製品長度方向延伸之假想線(FL1)更靠近製品寬度方向外側之區域內。
