A disposable diaper is provided with an outer body including a belly side portion and a back side portion, and an inner body. The belly side portion and back side portion of the outer body each has a plurality of waist elastic members extending in parallel to each other in the transverse direction. The outer body has an annular waist gather region, a belly side pressing region, a back side pressing region, and an annular tightening region. The area of the back side pressing region is smaller than the area of the belly side pressing region, and the contractile force of the back side pressing region is smaller than the contractile force of the belly side pressing region, and is no greater than 0.35N, and the contractile force per unit width of the tightening region is no less than 0.45N/25 mm.