The present invention on its first aspect provides a disposable diaper improved so as to prevent body waste from leaking sideways without sacrificing a bodily fluid absorbing capacity of a liquid-absorbent structure and to assure appropriate fitness to the wearers body. In each of front and rear waist regions 13, 14, a disposable diaper 10 comprises an upper elasticized region 18 extending in a vicinity of a waist-opening periphery 16a, lower elasticized regions 20A, 20B, intermediate elasticized region 19 extending between the upper elasticized region 18 and the lower elasticized regions 20A, 20B and outside longitudinally opposite ends 12a, 12b of a liquid-absorbent structure 12, and, at least in the front waist region 13 of the front and rear waist regions 13, 14, a non-elasticized region 30 opposed to a central zone of a liquid-absorbent core wherein a tensile stress of the intermediate elasticized region 19 is lower than a tensile stress of the upper elasticized region 18.第1發明提供一種,不會降低體液吸收性能,防止排泄物的側漏的同時,具有對穿用者身體的適度的貼合性的用後即棄式紙尿褲。又,第2發明提供一種,不會降低體液吸收性能,可防止體液的側漏的同時,具有顯著尿便保持性的用後即棄式紙尿褲。解決手段,用後即棄式紙尿褲(10)具有:在前後腰域(13、14),位在腰開口緣(16a)的附近的上側伸縮域(18);位在吸液性構造體(12)的側緣(112)外側的下側伸縮域(20A、20B);以及在上側伸縮域(18)與下側伸縮域(20A、20B)之間,位在吸液性構造體(12)的端緣部(12a、12b)的縱向外方的中間伸縮域(19),在前後腰域(13、14)中的至少前腰域(13),於下側伸縮域(20A、20B)間,在吸液性芯的中央域對向的位置形成有非伸縮域(30),中間伸縮域(19)的伸長應力變的比上側伸縮域(18)的伸長應力還小。25‧‧‧側緣部24‧‧‧側緣部18‧‧‧上側伸縮域19‧‧‧中間伸縮域20A、20B‧‧‧下側伸縮域35‧‧‧兩側部13‧‧‧前腰域12‧‧‧吸液性構造體30‧‧‧非伸縮域36‧‧‧摺邊31‧‧‧腰部彈性構件14‧‧‧後腰域32‧‧‧第2腰部彈性構件11‧‧‧主體15‧‧‧胯下域33‧‧‧第3腰部彈性構件16‧‧‧腰開口10‧‧‧用後即棄式紙尿褲16a‧‧‧腰部開口緣部61‧‧‧平面扣具的固定部60‧‧‧廢棄用平面扣具26‧‧‧接縫部36‧‧‧摺邊34‧‧‧腿部彈性構件17‧‧‧腿開口
