A pull-on disposable diaper has front and rear waist covering regions and a crotch covering region wherein a bodily discharge absorbing component extends over the crotch covering region into the front and rear waist covering regions. In the crotch covering region, the bodily discharge absorbing component is folded inward along first, second and third folding guides in a transverse direction of the absorbing component. A pair of flaps are formed along transversely opposite lateral side edges of the bodily discharge absorbing component. In each of the flaps, a first lateral marginal edge extending along the associated lateral edge is bonded to an outer surface of the bodily discharge absorbing component and a second lateral marginal edge lies on the side of an inner surface of the absorbing component. An elastic member is attached to the flap in a stretched state in a longitudinal direction of the flap.