There is provided a pull-on disposable diaper (1) including a lengthwise direction and a lateral direction orthogonal to each other, the pull-on disposable diaper including: a front side portion (30); a back side portion (40); a crotch portion (20); a waist opening BH; and a pair of leg openings (LH, LH). An edge portion (31BH) of the waist opening (BH) of the front side portion (30) includes a recessed portion (37) that is recessed in the lengthwise direction toward the crotch portion (20) with respect to an edge portion (41BH) of the waist opening (BH) of the back side portion (40). A tape member (48) is fixed on a non-skin side surface of the back side portion (40) so as to be extendable toward the waist opening (BH) in the lengthwise direction, the tape member (48) being used for fixing the diaper (1) in a small state in the lengthwise direction when the diaper (1) is disposed of. The recessed portion (37) is provided at a position corresponding to the tape member (48) in the lateral direction.