A disposable diaper (10) is provided with an absorbent body (absorbent body 40) having a pair of first fold lines (FL1) and a pair of second fold lines (FL2), and a back sheet 60a. In a folded state in which the absorbent body has been folded, the absorbent body includes: a first region (401) including the center, in the width direction, of the absorbent body a pair of second regions (402) which are located between the second fold lines and the first fold lines and are each disposed on a surface side of the first region that faces the skin and a pair of third regions (403) which are located to the outside, in the width direction, of the second fold lines, and which are each disposed on a surface side of the second region that faces the skin. Outside edges of the third regions are disposed to the outside, in the width direction, of the first fold lines. In the folded state there are provided: first joined portions (R1) where the first region and the second regions are joined third joined portions (R3) where the third regions and a non-skin surface sheet are joined and third non-joined portions (NR3) where the third regions and the non-skin surface sheet are not joined, positioned to the inside, in the width direction, of the third joined portions, and to the outside, in the width direction, of the first fold lines. The third non-joined portions extend in the front-back direction of the disposable diaper in a crotch area, and cross the center (1LC) in the front-back direction of the disposable diaper.用後即棄式紙尿布(10)具備有:吸收體(吸收體40),其是具有一對的第1折線(FL1)及一對的第2折線(FL2);以及背面薄片(60a)。吸收體在折疊吸收體的折疊狀態下,具有:包含吸收體的寬邊方向的中央的第1區域(401);一對的第2區域(402),其是位在第2折線與第1折線之間,並分別被配置在第1區域的肌膚對置面側;一對的第3區域(403),其是比第2折線更位於寬邊方向的外側,並分別被配置在第2區域的肌膚對置面側。第3區域的外側緣比第1折線更被配置在寬邊方向的外側。折疊狀態下,設有:接合第1區域與第2區域的第1接合部(R1)、接合第3區域與非肌膚面薄片的第3接合部(R3),以及第3非接合部(NR3),其是比其第3接合部更位在寬邊方向的內側,且比第1折線更位在寬邊方向的外側,沒有接合第3區域與非肌膚面薄片。第3非接合部,是跨用後即棄式紙尿布的前後方向的中心(1CL),且在胯下域朝前後方向延伸。10‧‧‧吸收性物品20‧‧‧前腰圍域25‧‧‧胯下域30‧‧‧後腰圍域35‧‧‧腿圍開口部40‧‧‧吸收體50‧‧‧頂面薄片70‧‧‧側薄片75‧
