PROBLEM TO BE SOLVED: To provide a disposable diaper which can suppress stimulation to skin of a wearer and can be positioned along the body of the wearer to inhibit leakage of a body fluid.SOLUTION: A disposable diaper 10 has a stretchable leg part 75, a stretchable crotch part 200 positioned under the crotch area, and an auxiliary sheet 55 positioned between a top sheet 50 and an absorbent body 40. The stretchable leg section is located further outside in the product width direction than the stretchable crotch section and extends further outward in the product length direction than the stretchable crotch section. A front edge 55F of the auxiliary sheet is positioned, in the product length direction, within the area between a rear edge 95R of a target section and a front edge 75F of the stretchable leg section. A rear edge 55R of the auxiliary sheet is positioned, in the product length direction, within the area between a rear edge 200R of the stretchable crotch section and a rear edge 75R of the stretchable leg section.