PROBLEM TO BE SOLVED: To provide a disposable diaper in which side panels excel in air permeability and fitting, and expansion/contraction characteristics of the side panels are hardly damaged even if strong tensile force is applied.SOLUTION: The disposable diaper 1 includes elastic side panels 3, 3 extended from both side edges of an absorbent body 2. The side panel 3 includes expanding/contracting section 30 to expand/contract in the X-direction. In the expanding/contracting section 30, a plurality of elastic members 33 are arranged at intervals in a Y-direction between two sheets of nonwoven fabrics 31, 32. The side panel 3 includes a plurality of serial junctions 35 to the distal end side in the X-direction. A plurality of elastic members 33 are fixed between the nonwoven fabrics 31, 32 in serial junction 35 via an adhesive continuously distributed in the Y-direction. Meanwhile, a middle expanding/contracting area 38 is provided between the proximal end 3b of the side panel and a serial junction part 35, wherein in the middle expanding/contracting area, the nonwoven fabrics 31, 32 are fused while distributed at a lot of fused-together parts 39 and the elastic members 33 are arranged not to pass those fused-together parts 39.
