The present invention is intended to provide the advantages of forming the leg creases with the liquid impermeable film which allows the reduction of the amount of non-sewn fabric used while suppressing texture deterioration, among others. the mentioned problem is solved by providing leg creases (60) having: an inner layer of non-sewn fabric (61) constituting an inner surface of the width direction； an outer layer of non-sewn fabric (62) constituting an outer surface of the width direction； elastically extensible folding materials (63) which are provided along the front-back direction between the inner layer of non-stitched fabric (61) and the outer layer of non-stitched fabric (62) of at least end portions front to intermediate parts of front-rear steering； and a liquid impermeable film (64) which is wrapped between the inner layer of non-stitched fabric and the outer layer of non-stitched fabric (62), extending from a base end to a position closest to one side. front end than the base end, and is configured such that portions of the leg folds (60) with the liquid impermeable film (64) are closer to the base end side than the front end portions constitute missing non-sewn fabric (65) wherein the inner layer of non-sewn fabric (61) does not exist and the liquid impermeable film (64) is exposed.a presente invenção se destina a fornecer as vantagens de formação das pregas de perna com o filme impermeável a líquido que permite a redução da quantidade utilizada de tecido não-costurado enquanto suprime a deterioração da textura, dentre outras. o problema mencionado é solucionado pelo fornecimento de pregas de perna (60) que têm: uma camada interior de tecido não-costurado (61) que constitui uma superfície interna da direção da largura； uma camada externa de tecido não-costurado (62) que constitui uma superfície externa da direção da largura； materiais de prega elasticamente extensíveis (63) que são fornecidos ao longo da direção frente-trás entre a camada interior de tec
