An absorbent body of a diaper has a central absorbent core, a pair of side absorbent cores and a pair of side elastic members. The side elastic members lie left and right of a front portion of the central absorbent core. The side absorbent cores lie left and right of rear and middle portions of the central absorbent core. In the diaper, by contraction of the side elastic members, the side absorbent cores come into close contact with the insides of thighs of a wearer, and urine is prevented from leaking from leg circumferences. Since the side absorbent cores are positioned left and right of the rear and middle portions of the central absorbent core, portions of the wearer's leg circumferences in the vicinity of the front are not covered with the side absorbent cores, and interference with leg movement of the wearer is prevented.