In this disposable diaper (10), leg-encircling indentations (35) are formed that are indented towards the center in the product widthwise direction (W) of an absorbent main body (15) at the lateral edges in the product widthwise direction (W) of the absorbent main body (15). The ends in the product widthwise direction (W) of a side flap (70) have a meandering shape in the product lengthwise direction (L) the distance between a center line (CL) and the ends in the product widthwise direction (W) of the side flap (70) changes from a front waist-encircling section (20) towards a back waist-encircling section (30) and a protrusion (130) formed by means of the change in distance is provided at least to a groin section (25).本發明之課題在提供一種,一面確實防止排泄物的洩漏,一面進一步減低對穿用者的腿圍部周邊的肌膚的刺激的用後即棄式紙尿布。解決手段,用後即棄式紙尿布(10),係具備有:被設在側翼(70)的製品寬幅方向(W)的側端部,延伸存在於製品長方向(L),並且至少沿著製品長方向(L)一部份可伸縮的薄片狀的腿圍伸縮部(100)。腿圍伸縮部(100)的製品寬幅方向(W)的端緣,在製品長方向(L)呈蛇行狀,腿圍伸縮部(100)的製品寬幅方向(W)的端緣、與中心線(CL)的距離,是從前腰圍部(20)朝向後腰圍部(30)連續變化,藉由該距離的變化量從增加轉成減少所形成的凸部(130),是被設在胯下部(25)。10‧‧‧用後即棄式紙尿布15‧‧‧吸收性本體80‧‧‧腿側褶邊70‧‧‧側翼90‧‧‧黏扣帶30‧‧‧後腰圍部25‧‧‧胯下部20‧‧‧前腰圍部200‧‧‧伸縮薄片100‧‧‧腿圍伸縮部d1‧‧‧距離d2‧‧‧距離CT‧‧‧中心40‧‧‧吸收體65‧‧‧目標帶片
