An adult diaper in which operability in detachably connecting side edge portionsof front and rear waist regions together is improved. The adult diaper has a frontwaist region (2), a rear waist region (3), and a crotch region (4) between them. The side edge portions (5, 6) of the front and rear waist regions are detachablyengaged with each other to form both a waist opening (7) and a pair of leg opening(8). The length in the longitudinal direction (Y) of the side edge portions (5,6) is at least 150 mm. The adult diaper further has means for facilitating adjustmentof the relative positions of first and second fastening components when the frontand rear waist regions are coupled, and the means has at least one separation regiondefined between two or more installation regions formed by splitting the firstfastening component and arranging them vertically.
