The present invention is provided with: a step for conveying a composite sheet 30mf in which a plurality of elastic members 35a, 35a…, which extend along the conveyance direction in a state of being stretched in the conveyance direction, are interposed and fixed, in a state of being arranged in the CD direction, which intersects the conveyance direction, between a first non-woven fabric 30mf1 which is continuous in the conveyance direction, and a second non-woven fabric 30mf2 which is provided overlapping the first non-woven fabric 30mf1 in the thickness direction, and which is continuous in the conveyance direction a step S50 in which push-in members 55p are pushed in the thickness direction into positions between adjacent elastic members 35a, 35a in the composite sheet 30mf in the CD direction, to form through holes h in the composite sheet 30mf a step S60 in which a tensile force is applied to the composite sheet 30mf in the CD direction at a position located further downstream than a through-hole-formation processing position P51 where the through holes h are formed in step S50 and a step S70 in which the composite sheet 30mf is processed at a position located further downstream in the conveyance direction than a tensile force application position P60 where the tensile force is applied in step S60.La présente invention comprend : une étape de transport dune feuille composite 30 mf dans laquelle sont interposés et fixés une pluralité déléments élastiques 35a, 35a … qui sétendent dans la direction de transport dans un état détirement dans la direction de transport, dans un état dagencement dans le sens de la largeur (CD) qui coupe la direction de transport, entre un premier tissu non tissé 30mf1 qui est continu dans la direction de transport, et un second tissu non tissé qui est disposé de manière à chevaucher le premier tissu non tissé dans la sens de lépaisseur, et qui est continu dans la direction de transport une étape S50 dans laquelle des éléments denfoncem
