To easily open a side flap portion at the time of attachment and flexibly touch the side edge of a side flap.SOLUTION: The above-mentioned problem is solved by the fact that the portion located at least in the crotch in each side flap portion SF includes a base portion 71 extending sideways from the main body portion 10, and a base portion 71 folded back to the center side in the width direction WD at the side edge of the base portion 71 And a folded-back portion 72. At a portion of the folded-back portion 72 located at least in the middle of the front-rear direction LD, there is a joining portion 73 joined to the base portion 71 on the front end side of the folded-back portion 72, and a joining portion 73 is a non-joined portion 74 which is not joined to the base portion 71 as a whole, and a portion located on the front side out of the base portion 71 and the folded-back portion 72 is formed with a width direction WD A side elastic member 75 extending inward in the front-rear direction LD passing through a position is provided, and in the natural length state, as the side elastic member 75 contracts, the side flap portion SF Is contracted in the longitudinal direction LD, it is solved by.(Fig.【課題】装着に際してサイドフラップ部が容易に開くようにするとともに、サイドフラップの側縁の肌触りを柔軟にする。【解決手段】上記課題は、各サイドフラップ部SFにおける少なくとも股間に位置する部分は、本体部10から側方に延びる基部71と、この基部71の側縁で幅方向WD中央側に折り返された折り返し部72とを有し、折り返し部72における少なくとも前後方向LDの中間に位置する部分では、折り返し部72の先端側に基部71と接合された接合部73を有するとともに、折り返し部72における接合部73よりも側方全体は基部71と接合されていない非接合部74となっており、基部71及び折り返し部72のうち表側に位置する方には、非接合部74の側縁から幅方向WD内側に離れた位置を通り前後方向LDに延在するサイド弾性部材75が設けられ、自然長状態では、サイド弾性部材75の収縮に伴いサイドフラップ部SFが前後方向LDに収縮される、ことにより解決される。【選択図】図11
