An open-type disposable diaper includes a crotch stretch unit formed in an absorber arrangement region where an absorber is arranged in a crotch region and being stretchable in a product longitudinal direction a pair of leg stretch units formed along a leg hole openings and being stretchable in at least the product longitudinal direction and a waist stretch unit formed in a back waistline region and being stretchable in a product widthwise direction the absorber core arrangement region enclosed by the crotch stretch unit, the leg stretch units, and the waist stretch unit and configuring the absorber is formed so as not to be stretched. The length of the absorber core arrangement region in the product longitudinal direction is configured to be longer than half the length of the crotch stretch unit in the product longitudinal direction.
