A disposable diaper which is provided with a waist opening and a pair of leg openings, wherein the disposable diaper includes a longitudinal direction and a transverse direction which is perpendicular to the longitudinal direction, a composite stretchable member is provided at least at side parts of a waist part which is positioned between the waist opening and the leg openings of the disposable diaper, the composite stretchable member is provided with a first nonwoven fabric sheet part and a second nonwoven fabric sheet part which are mutually overlaid as well as elastic members which are arranged between the first nonwoven fabric sheet part and the second nonwoven fabric sheet part, each of the first nonwoven fabric sheet part and the second nonwoven fabric sheet part is provided with: a plurality of convex-concave regions which are pro-vided with convex parts and concave parts which are alternately repeated along the transverse direction and which extend in the longitudinal direction and at least one non-shaped region which separates these convex-concave regions from each other in the longitudinal direc-tion, the first nonwoven fabric sheet part and the second nonwoven fabric sheet part are overlaid so that the convex-concave regions of the first nonwoven fabric sheet part and the second nonwoven fabric sheet part adjoin each other and the non-shaped regions of the first nonwoven fabric sheet part and the second nonwoven fabric sheet part are separated from each other and so that the convex-concave regions and the non-shaped regions are respectively aligned in the longitudinal direction, and the first nonwoven fabric sheet part and the second nonwoven fabric sheet part are joined with each other by an adhesive which is applied to the elastic members, wherein the convex parts of the first nonwoven fabric sheet part enter into the concave parts of the second nonwoven fabric sheet part and wherein the convex parts of the second nonwoven fabric sheet part enter into the concave parts of the first nonwoven fabric sheet part. the disposable diaper includes a longitudinal direction and a transverse direction which is perpendicular to the longitudinal direction, a composite stretchable member is provided at least at side parts of a waist part which is positioned between the waist opening and the leg openings of the disposable diaper, the composite stretchable member is provided with a first nonwoven fabric sheet part and a second nonwoven fabric sheet part which are mutually overlaid as well as elastic members which are arranged between the first nonwoven fabric sheet part and the second nonwoven fabric sheet part, each of the first nonwoven fabric sheet part and the second nonwoven fabric sheet part is provided with: a plurality of convex-concave regions which are pro-vided with convex parts and concave parts which are alternately repeated along the transverse direction and which extend in the longitudinal direction and at least one non-shaped region which separates these convex-concave regions from each other in the longitudinal direc-tion, a plurality of convex-concave regions which are pro-vided with convex parts and concave parts which are alternately repeated along the transverse direction and which extend in the longitudinal direction and at least one non-shaped region which separates these convex-concave regions from each other in the longitudinal direc-tion, the first nonwoven fabric sheet part and the second nonwoven fabric sheet part are overlaid so that the convex-concave regions of the first nonwoven fabric sheet part and the second nonwoven fabric sheet part adjoin each other and the non-shaped regions of the first nonwoven fabric sheet part and the second nonwoven fabric sheet part are separated from each other and so that the convex-concave regions and the non-shaped regions are respectively aligned in the longitudinal direction, and the first nonwoven fabric sheet part and the second nonwoven fabric sheet part are joined with each other by an adhesive which is applied to the elastic members, wherein