A disposable diaper includes a chassis, front and rear waist regions, and a crotch region between the front and rear waist regions and a liquid-absorbent structure extending at least in the crotch region. The chassis includes a pair of first leg elastics, and a pair of second leg elastics. The first leg elastics are arranged so as to be rectilinear in the longitudinal direction. The second leg elastics are arranged at a distance from the longitudinal axis as viewed in the transverse direction larger than a distance from the longitudinal axis at which the first leg elastics are arranged and have rectilinear portions extending in the longitudinal direct at least in a portion of the crotch region close to the front waist region and curved portions spaced apart outwardly from each other from the rear waist region side ends of the rectilinear portions.