A disposable diaper (1) is provided with: a diaper body (10) having a plurality of elastic members, which are positioned farther to the outside in the width direction than an absorbent body in a stretched state in the longitudinal direction of the absorbent body dorsal side flaps (20) that extend further to the outside in the width direction than the diaper body and joining sections (51) that join the dorsal side flaps (20) and the diaper body. A first elastic member 123a and a first elastic member 124a, which are positioned farthest to the outside in the width direction among the plurality of elastic members, overlap with the joining sections in the thickness direction (T) of the disposable diaper in a stretched state in the longitudinal state.本發明之課題在提供一種,沿著穿用者的腿圍配置構成腿部皺褶的伸縮性構件,可提昇在腿圍的貼合性之用後即棄式紙尿布。解決手段,用後即棄式紙尿布(1)是具備有:尿布本體(10),該尿布本體(10)具有沿著吸收體的長方向在被伸長的狀態下被配置在比吸收體更位在寬方向外側的複數個伸縮性構件;比尿布本體更朝寬方向外側延伸突出的背側側翼(20);以及接合背側側翼(20)與尿布本體的接合部(51)。複數個伸縮性構件中最位在前述寬方向外側的第1伸縮性構件(123a)及第1伸縮性構件(124a),是沿著長方向被伸長的狀態下,在用後即棄式紙尿布的厚度方向T重疊在接合部。30‧‧‧腹側側翼41‧‧‧固定構件20‧‧‧背側側翼124a‧‧‧第1伸縮性構件124b‧‧‧第1伸縮性構件
