A manufacturing method and manufacturing device of an elastic composite sheet are provided which enable easily manufacturing an elastic composite sheet having desired characteristics. An elastic resin material having a thermoplastic elastic resin as the main component is heated and melted, and the elastic resin material is discharged in a film or a linear shape from a discharge mechanism (20) to form a film-shape or a linear-shape intermediate product (2). At a temperature above than the temperature region at which the elastic resin material elastically deforms, stretching is performed until the thickness or width of the film-shape intermediate product (2) or the thickness of the linear-shape intermediate product (2) assumes a prescribed value； with a cooling roller (3), the intermediate product (2) is cooled to the temperature region at which the elastic resin material elastically deforms, and the intermediate product is hardened, forming a film-shape or linear-shape elastic member (3). The elastic member (3) is stretched with a stretch roller (40) to a prescribed stretching ratio, and the stretched elastic member (3) is laminated on and bonded to a first base material sheet (4). Preferably, the elastic member (3) is laminated between the first and a second base material sheet (4, 6).L'invention concerne une méthode de fabrication et un dispositif de fabrication d'une feuille composite élastique qui permettent de fabriquer facilement une feuille composite élastique ayant des caractéristiques souhaitées. Un matériau de résine élastique ayant une résine élastique thermoplastique en tant que composant principal est chauffé et fondu, et le matériau de résine élastique est déchargé en un film ou une forme linéaire à partir d'un mécanisme de décharge (20) pour former un produit intermédiaire de forme linéaire ou de forme de film (2). À une température supérieure à la zone de température à laquelle le matériau de résine élastique se déforme élastiquement, un étirement est
