To prevent the occurrence of a situation in which a base piece separates from a diaper by shifting a position of a point of action upon developing a self-adhesive tape, from connection point where the base piece and an intermediate piece are connected to each other.

The disposable diaper with a self-adhesive tape and a post-processing tape includes the intermediate piece 2. In one end of the intermediate piece 2 on a side of a connection point where the intermediate piece 2 is continuous with the base piece 1, the intermediate piece 2 is folded back in a direction in which a self-adhesive layer 2a on one side and that on the other side adhere to each other, the self-adhesive layer 2a being provided on a rear surface of the intermediate piece 2. The intermediate piece 2 includes: a mold-release layer adhesion part 21 where the self-adhesive layer provided on the rear surface of the intermediate piece 2 adheres to a mold-release layer 1b provided on a surface of the base piece; a folded back adhesion part 22 where the self-adhesive layer on one side and that on the other side adhere to each other, the self-adhesive layer being provided on a rear surface of the intermediate piece 2; and a self-adhesive layer adhesion part 23 which is disposed between the base piece and an object 100 and in which the self-adhesive layer provided on the rear surface of the intermediate piece adheres to a self-adhesive layer 1a provided on the rear surface of the base piece.