A disposable diaper includes a side flap and a tape fastener. The tape fastener includes a tape attaching part attached to the side flap and exposed at an outer side face of the side flap. The side flap includes a leg periphery side region positioned closer to a leg of a wearer than the tape attaching part. The leg periphery side region is foldable upwardly to cover at least partially an end portion of the tape attaching part adjacent the leg of the wearer in response to a stress generated when the tape fastener is engaged, while being pulled, with the other end portion of the inner part in the longitudinal direction.
