PROBLEM TO BE SOLVED: To provide an underpants type absorbent article which can achieve excellent fitness and wearability.SOLUTION: An underpants type absorbent article (1) includes an absorbent body (10) with an absorbent core (11A), and the absorbent body (10) is double-folded at a prescribed position (FL) in a front-back direction so as to form a pair of leg opening parts (LH). In a part located inside a leg opening elastic member (17) and outside an outer edge of the absorbent core (11A) in a horizontal direction, an inner elastic member (18) that can be expanded and contracted along the leg opening part (LH) is provided. In a vertical direction, a length of a part where expanding/contracting properties of the inner elastic member (18) are expressed on the front side with respect to the prescribed position (FL) is longer than a length of a part where the expanding/contracting properties of the inner elastic member (18) are expressed on the back side with respect to the prescribed position (FL).SELECTED DRAWING: Figure 3COPYRIGHT: (C)2020,JPO&INPIT【課題】良好なフィット性や着用性を実現可能なパンツ型吸収性物品を提供する。【解決手段】吸収性コア（１１Ａ）を備えた吸収性本体（１０）を有し、吸収性本体（１０）が前記前後方向の所定位置（ＦＬ）にて二つ折りにされ、一対の脚回り開口部（ＬＨ）が形成されているパンツ型吸収性物品（１）であって、左右方向において、脚回り弾性部材（１７）よりも内側、かつ、吸収性コア（１１Ａ）の外縁よりも外側には、脚回り開口部（ＬＨ）に沿って伸縮可能な内側弾性部材（１８）が設けられており、上下方向において、所定位置（ＦＬ）よりも前側で内側弾性部材（１８）の伸縮性が発現している部分の長さは、所定位置（ＦＬ）よりも後側で内側弾性部材（１８）の伸縮性が発現している部分の長さよりも長い。【選択図】図３
