PROBLEM TO BE SOLVED: To provide an underpants type disposable diaper in which wrinkles hardly occur on an absorber arranged on a crotch area, and in which preferable fitness on a pair of leg opening parts can be maintained.SOLUTION: In an expanded and stretched state of a diaper 1, a pair of leg gatherings 80, 80 are formed by an abdominal side leg elastic member 81a and a back side leg elastic member 81b arranged along respective opening peripheral edge parts of a pair of leg opening parts 8, 8. The abdominal side leg elastic member 81a and the back side leg elastic member 81b cross on a side closer to an abdominal area A side than to a lateral center line Yc which divides the diaper 1 into half in a vertical direction Z, and are fixed to an exterior body 10 by an adhesive in inside of the lateral direction Y relative to the crossing part. On a center part of the crotch area C, the back side leg elastic member 81b is arranged so that an angle α formed by the back side leg elastic member 81b and both side edges 46, 46 along the vertical direction X of the absorber 4 becomes 30 degree or more and 90 degree or less.SELECTED DRAWING: Figure 2COPYRIGHT: (C)2018,JPO&INPIT【課題】股下領域に配された吸収体上に皺を発生し難くすると共に、一対のレッグ開口部における良好なフィット性を維持すること。【解決手段】おむつ1の展開且つ伸長状態において、一対のレッグ開口部8,8それぞれの開口周縁部に沿って配された腹側レッグ弾性部材81a及び背側レッグ弾性部材81bにより一対のレッグギャザー80,80が形成されている。腹側レッグ弾性部材81aと背側レッグ弾性部材81bとは、股下領域Cの中央部において、おむつ1を縦方向Xに二分する横中心線Ycよりも腹側領域A側で交差しており、交差している部分よりも横方向Yの内方で接着剤により外装体10に固定されている。股下領域Cの中央部において、背側レッグ弾性部材81bと吸収体4の縦方向Xに沿う両側縁46,46それぞれとのなす角αが、30度以上90度以下となるように背側レッグ弾性部材81bが配されている。【選択図】図2
