To improve the ventilation properties of a sheet used in a flute structure. This disposable diaper has formed therein, on at least one of a front part and a rear part, a cushion part (40). In the cushion part (40), in a state where a waist expansion member (43) is stretched in the width direction of the diaper, the member is sandwiched and secured between an inner sheet (41) and an outer sheet (42). In the cushion part (40), a cushion forming sheet (44) overlaps one or both of the inner sheet (41) and the outer sheet (42), and is intermittently joined thereto so that in the width direction joining portions (51) and non-joining portions (52) are alternatingly continuous. Formed in the cushion forming sheet (44) are a plurality of openings (60) or depressions that are grouped into row groups (R) and column groups (C). A continuous line (A) links the plurality of openings (60) or depressions which belong to the column group (C), and the line is inclined at a prescribed angle ([Theta]) with respect to a reference line (F) that extends in the longitudinal direction.本發明的課題係提升溝紋構造中所採用之片材的透氣性。本發明的拋棄式尿布，在正面部與背面部的至少一邊形成緩衝部40。緩衝部40中，腰部伸縮構件43在沿著尿布的寬度方向伸長的狀態下，被夾入內側片材41與外側片材42間而固定。緩衝部40中，緩衝形成片材44，與內側片材41和外側片材42的兩者或是任一者重合，而在寬度方向上間隔性地接合，形成接合部51與非接合部52連續交錯的態樣。緩衝形成片材44中，形成區分為列群組(R)與行群組(C)的複數個開孔60或凹槽。將屬於行群組(C)的複數個開孔60或凹槽連結的連結直線(A)，以既定角度(θ)相對沿著長度方向延伸的基準直線(F)傾斜。
