A disposable pants-type diaper includes a separator interposed between the inner surface of a pants-type skin-covering assembly and the wearer's skin so as to protect the wearer's skin from being soiled with feces. The separator comprises a separator extending from a bottom of a crotch region of the diaper toward a front waist region and a rear waist region and fixed to the crotch region along transversely opposite margins thereof. The separator has a front end and a rear end both extending in a transverse direction of the crotch region and elastically extensible and contractible. In a transversely middle of the crotch region, these front and rear end edges are spaced from the inner surface of the absorbent chassis and joined integrally with each other.