An absorbent article having a longitudinal direction, a lateral direction intersecting the longitudinal direction, and a front-back direction intersecting the longitudinal direction and the lateral direction, the absorbent article comprising: a front waist portion extending along the lateral direction; a back waist portion extending along the lateral direction; and a crotch portion provided between the front waist portion and the back waist portion, a one-side end portion of the back waist portion on a one side in the lateral direction being joined by a first joining portion to a one-side end portion of the front waist portion on the one side in the lateral direction, the back waist portion including an elastic region (X) and a fastening portion on an other side in the lateral direction, the elastic region (X) stretching/contracting in the lateral direction, the fastening portion being capable of being fastened to the front waist portion when putting on the absorbent article, while the fastening portion being fastened to the front waist portion so that an end of the fastening portion on a side closer to the elastic region (X) is positioned in the lateral direction on an end of the crotch portion opposite to the first joining portion , the elastic region (X) being located on a non-skin side of an other-side end portion of the front waist portion on the other side in the lateral direction, and having a stacking part in which the elastic region (X) is stacked on the other-side end portion of the front waist portion, the other-side end portion of the front waist portion not having stretchability. a front waist portion extending along the lateral direction; a back waist portion extending along the lateral direction; and a crotch portion provided between the front waist portion and the back waist portion, a one-side end portion of the back waist portion on a one side in the lateral direction being joined by a first joining portion to a one-side end portion of the front waist portion on the one side in the lateral direction, the back waist portion including an elastic region (X) and a fastening portion on an other side in the lateral direction, the elastic region (X) stretching/contracting in the lateral direction, the fastening portion being capable of being fastened to the front waist portion when putting on the absorbent article, the elastic region (X) stretching/contracting in the lateral direction, the fastening portion being capable of being fastened to the front waist portion when putting on the absorbent article, while the fastening portion being fastened to the front waist portion so that an end of the fastening portion on a side closer to the elastic region (X) is positioned in the lateral direction on an end of the crotch portion opposite to the first joining portion , the elastic region (X) being located on a non-skin side of an other-side end portion of the front waist portion on the other side in the lateral direction, and having a stacking part in which the elastic region (X) is stacked on the other-side end portion of the front waist portion, the other-side end portion of the front waist portion not having stretchability. the elastic region (X) being located on a non-skin side of an other-side end portion of the front waist portion on the other side in the lateral direction, and having a stacking part in which the elastic region (X) is stacked on the other-side end portion of the front waist portion, the other-side end portion of the front waist portion not having stretchability. <EOS>