A disposable pull-on type diaper has a separator interposed between an inner surface of an absorbent chassis and the wearers skin so as to protect the diaper wearers skin from being soiled with feces. The separator is formed by a piece of sheet extending from a bottom of a crotch region of the diaper toward a front waist region and a rear waist region and fixed to lateral edges of the crotch region. The piece of sheet has a front end and a rear end both extending in a transverse direction of the crotch region. These front end and rear end are free along middle segments thereof as viewed in the transverse direction of the crotch region from an inner surface of an absorbent chassis and inseparably integrated with each other.