Provided is an absorbent article in which suitability to a body can be improved while improving a feeling of wearability for a wearer, and these features can be recognized from an external appearance. An absorbent article (1) comprises an absorbent main body (AB), and a pair of side flaps (SF, SF) that extend toward outer sides from both width direction end sections of the absorbent main body. Each of the pair of side flaps comprises a sheet-shaped expansion/contraction member (12) that can expand/contract in the width direction, and sheet members (7a, 7b) that are respectively laminated to both thickness direction surfaces of the expansion/contraction member. Each of the pair of side flaps has an expansion/contraction member placement section (Ea) in which the expansion/contraction member and the sheet members overlap in the thickness direction, and extension sections (Pa, Pb) in which the sheet members extend to both length direction outer sides of the expansion/contraction member placement section. The sheet members are formed from a nonwoven fabric, and while the side flaps are at a natural length, the extension sections have a plurality of wrinkles (17s) that follow along the length direction and are lined up in the width direction.
