A disposable diaper has a diaper main body including a plurality of elastic members arranged in an extended state along a longitudinal direction of the absorber, at outer sides in a widthwise direction with respect to the absorber, a dorsal side flap protruded toward outer sides in the widthwise direction with respect to the diaper main body, at an outer end in the longitudinal direction of the diaper main body and a joining unit configured to join the side flap and the diaper main body. The elastic member positioned at outermost sides in the widthwise direction out of the plurality of elastic members are overlapped in an extended state in the longitudinal direction, with the joining unit in a thickness direction of the disposable diaper.
