[PROBLEMS] A disposable diaper in which displacement and deformation of an absorption pad caused by movement of the body of a wearer are prevented to prevent leakage. [MEANS FOR SOLVING PROBLEMS] A portion corresponding to a first portion in the longitudinally middle of an inner elastic member (13i) is a not-fixed region (14) where a back sheet (1) and an exterior sheet (12) are not fixed. Portions corresponding to second portions on longitudinally both sides of the first portion are fixed regions where the back sheet (1) and the exterior sheet (12) are fixed. That portion of the inner elastic member (13i) which is in the not-fixed region (14) is fixed to nether the back sheet (1) nor the exterior sheet (12) or is fixed only to the exterior sheet (12). Those portions of the inner elastic member (13i) which are in the fixed regions are fixed to the back sheet (1) and the exterior sheet (12).