This disposable diaper (10) is provided with a sheet-shaped leg-encircling expanding/contracting section (100) that extends in the product lengthwise direction (L) at a region to which a leg-encircling indentation (35) is formed, and has a portion that can expand/contract along at least the product lengthwise direction (L). The ends in the product widthwise direction (W) of the leg-encircling expanding/contracting section (100) 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 leg-encircling expanding/contracting section (100) changes from a front waist-encircling section (20) along towards a back waist-encircling section (30) and there are a plurality provided each of inflection points at which the amount of change in distance shifts from increasing to decreasing, and inflection points at which the amount of change in distance shifts from decreasing to increasing.本發明的課題係在於提供既可確實地防止排泄物的洩漏,又可進一步減低對穿用者的腳圍部周邊的肌膚之刺激的用後即棄式紙尿布。用以解決課題之手段為,用後即棄式紙尿布(10)係具備:在形成有腳圍凹部(35)的區域,朝製品長度方向(L)延伸,並且一部分可至少延著製品長度方向(L)伸縮之薄片狀的腳圍伸縮部(100)。腳圍伸縮部(100)的製品寬度方向(W)之端緣係在製品長度方向(L)呈蛇形狀,腳圍伸縮部(100)的製品寬度方向(W)之端緣與中心線(CL)之距離係隨著從前腰圍部(20)朝後腰圍部(30)變化,距離的變化量從增加轉為減少之反曲點的數量、距離的變化量從減少轉變成增加之反曲點的數量分別設有複數個。10‧‧‧用後即棄式紙尿布15‧‧‧吸收性本體20‧‧‧前腰圍部25‧‧‧胯下部30‧‧‧後腰圍部40‧‧‧吸收層70‧‧‧側翼片80‧‧‧腳側皺褶90‧‧‧扣帶100‧‧‧腳圍伸縮部200‧‧‧伸縮薄片65‧‧‧目標帶
