Provided is an absorbent article that can improve the fit of the wearer while improving the fit to the body and can recognize it from the appearance. The absorbent article (1) includes an absorbent main body (AB) and a pair of side flaps (SF, SF) extending outward from both ends in the width direction of the absorbent main body. Each of the pair of side flaps includes a sheet-like stretchable member 12) that can be stretched in the width direction, and sheet members (7a, 7b) that are laminated on both sides in the thickness direction of the stretchable member. The expansion / contraction member and the sheet member overlap in the direction, and the expansion / contraction member arrangement part (Ea) and the extension part (Pa, Pb) each extending the sheet member on both outer sides in the longitudinal direction of the expansion / contraction member arrangement part. The sheet member is formed of a nonwoven fabric, and the extending portion has a plurality of ridges (17S) arranged in the width direction along the longitudinal direction when the side flap is in a natural length state.身体への適合性を向上しつつ、装着者の装着感を向上でき、外観からそれを認識することが可能な吸収性物品を提供する。吸収性物品（１）は、吸収性本体（ＡＢ）と、吸収性本体の前記幅方向の両端部から外側に延出する一対のサイドフラップ（ＳＦ、ＳＦ）と、を備える。一対のサイドフラップの各々は、幅方向に伸縮可能なシート状の伸縮部材１２）と、伸縮部材の厚さ方向の両面にそれぞれ積層されたシート部材（７ａ、７ｂ）と、を備え、厚さ方向に伸縮部材とシート部材とが重なる伸縮部材配置部（Ｅａ）と、伸縮部材配置部の長手方向の両外側にそれぞれシート部材が延出した延出部（Ｐａ、Ｐｂ）と、を有する。シート部材は、不織布で形成されており、延出部は、サイドフラップが自然長の状態時に、長手方向に沿い、幅方向に並んだ複数の皺（１７Ｓ）を有する。
