An absorbent article (1) includes: an absorbent main body (10) including an absorbent core (40) ; and a pair of leak-proof walls (20) . The pair of leak-proof walls (20) are provided on respective widthwise side portions of the absorbent main body (10) . Each of the leak-proof walls (20) is capable of standing on a skin side in the thickness direction, and includes a skin-side portion (23) and a non-skin-side portion (24). The absorbent core (40) includes a low-basis-weight portion (43) in a widthwise central portion, and the low-basis-weight portion (43) is a portion in which a basis weight of the absorbent core (40) is smaller than the basis weight in a surrounding of the portion. A joined part (27) is formed by joining at least partially a surface of the skin-side portion (23) and a surface of the non-skin-side portion (24), the surfaces facing to each other. The joined part (27) is provided inside a distal end of the leak-proof wall (20) and outside the low-basis-weight portion (43) in the width direction. A part of the joined part (27) and a part of the low-basis-weight portion (43) at least overlapping in the longitudinal direction.