A diaper (10) includes an absorbent assembly (20) including a topsheet (21), a backsheet (22), and an absorbent core (24), and has an article longitudinal direction (X) and an article lateral direction (Y). The absorbent core (24) is formed of a sheet-like article (1) including a plurality of absorbent units (4), each including a long base portion (2) and water-absorbent polymer particles (3). The sheet-like article (1) includes a plurality of unit portions arranged in the longitudinal direction (x1 direction), each unit portion including a plurality of the absorbent units (4) arranged side by side in the lateral direction (y1 direction). The sheet-like article (1) includes a pair of longitudinal joined regions (41, 41), a pair of lateral joined regions (42, 42), and intermediate lateral joined regions (43, 43). The sheet-like article (1) is joined to a constituent member adjacent thereto in the thickness direction (Z) at the pair of longitudinal joined regions (41, 41), the pair of lateral joined regions (42, 42), and the intermediate lateral joined regions (43, 43). Each unit portion includes a section in which neither the upper side nor the lower side thereof in the thickness direction (Z) is joined to the constituent member.
