A disposable diaper, having a longitudinal direction and a lateral direction, an absorbent main body having an absorbent body, a back waist part located on one end of the absorbent main body, and an abdominal waist part located on another end of the absorbent body, the absorbent body having side parts in the lateral direction provided with a pair of embossed lines formed by embossing from a skin side of the absorbent body, and the embossed lines each including a protrusion point, protruding inward in the lateral direction, located in a center of the disposable diaper in the longitudinal direction in a midsection of the disposable diaper or on a back waist part side with respect to the center, and a back line, linear or curved outward, extending outward in the lateral direction from the protrusion point, as a starting point, toward the back waist part in the longitudinal direction.