PROBLEM TO BE SOLVED: To provide an underpants-type absorbent article in which an outer wrapping material is divided into an abdomen-side sheet member and a back-side sheet member, and which is excellent in covering property of wearers buttocks.SOLUTION: The underpants-type absorbent article 1 is a type with the outer wrapping material divided into a front and a back portions, which has the abdomen-side sheet member 2A, the back-side sheet member 2B and an absorbent body 3. The back-side sheet member 2B has a back-side extension part 21b extending downward from a side seal part 4. The absorbent body 3 has a vertically long absorbent body 33 and a side sheet part 34. The side sheet part 34 has a stretching area 34c exhibiting elasticity by an elastic member 36 fixed in an extended state on a crotch part C and the back-side extension part 21b. A back-side vertically stretching part Eb is formed with the stretching area 34c connected to at least the back-side extension part 21b of the back-side sheet member 2B. By the contraction of the stretching part Eb, a part Pb bent convexly upward is generated in the lower edge part 2d near the stretching part Eb of the back-side sheet member 2B in a natural state.COPYRIGHT: (C)2012,JPO&INPIT【課題】外包材が、腹側シート部材と背側シート部材とに分割されたタイプのパンツ型吸収性物品であって、着用者の臀部の被覆性に優れたパンツ型吸収性物品を提供すること。【解決手段】腹側シート部材2A、背側シート部材2B及び吸収性本体3を有する外包材前後分割タイプのパンツ型吸収性物品1であり、背側シート部材2Bは、サイドシール部4より下方に延出する背側延出部21bを有し、吸収性本体3は、縦長の吸収体33及び側部シート部34を有する。側部シート部34は、股下部C及び背側延出部21b上に、伸長状態で固定された弾性部材36により伸縮性を示す伸縮領域34cを有し、背側シート部材2Bの少なくとも背側延出部21bに、伸縮領域34cが接合されて背側縦伸縮部Ebが形成され、該伸縮部Ebの収縮により、自然状態における背側シート部材2Bの該伸縮部Eb付近の下縁部2dに、上方に向けて凸に屈曲した部分Pbが生じている。【選択図】図1
