Provided is a disposable underpants-type diaper which does not make the wearer feel that the outer surface of a bodily fluid absorbent structure is leaking. This disposable underpants-type diaper (10) comprises an outer cover (15) and a bodily fluid absorbent structure (20). The bodily fluid absorbent structure (20) includes a liquid-impermeable and moisture-permeable plastic film (39a) on the outer surface side and is bonded to the inner surface (18) of a front waist region (12) and of a rear waist region (13) of the outer cover (15). In the bodily fluid absorbent structure (20), at least a portion of the center (20a) in the horizontal direction (B), and both sides (20b) in the horizontal direction (B) are linked in the horizontal direction (B) in a state not bonded to the crotch area (14) of the outer cover (15). In the outer cover (15), gathers (40) are formed by contraction of an elastically contractible sheet (30) in the horizontal direction (B).本發明之課題在提供一種,不會感受到體液吸收部的外面有濕掉的情況的用後即棄式短褲型紙尿褲。短褲型用後即棄式紙尿褲(10)具有被覆部(15)與體液吸收部(20)。體液吸收部(20),是在外面側包含不透液性且透濕性的塑膠薄膜(39a),且接合在被覆部(15)中的前腰圍域(12)與後腰圍域(13)的內面(18)。體液吸收部(20)又在橫向(B)中的中央部(20a)的至少一部分與兩側部(20b)相對於被覆部(15)的胯下域(14)處於非接合的狀態,而在橫向(B)連接。被覆部(15),是藉由在橫向(B)可反覆地彈性伸長與收縮的薄片狀構件(30)的收縮形成有皺褶(40)。5‧‧‧熱熔接著劑12‧‧‧前腰圍域12a‧‧‧側緣部12b‧‧‧腰圍開口緣部13‧‧‧後腰圍域13a‧‧‧側緣部13b‧‧‧腰圍開口緣部14‧‧‧胯下域14a‧‧‧最下部14b‧‧‧兩側緣部15‧‧‧被覆部18‧‧‧內面19‧‧‧外面20‧‧‧體液吸收部20a‧‧‧中央部20b‧‧‧兩側部21‧‧‧前端部22‧‧‧後端部23‧‧‧帶構件25‧‧‧兩側緣30‧‧‧薄片狀構件41‧‧‧防漏壁43‧‧‧彈性構件110‧‧‧伸展紙尿褲B‧‧‧橫向C‧‧‧前後方向E1‧‧‧尺寸E2‧‧‧尺寸F‧‧‧尺寸G‧‧‧範圍H‧‧‧接合域
