A mother element substrate and a mother seal substrate are adhered with each other via an adhesive sheet. An adhesive sheet cut portion of the adhesive sheet corresponding to a terminal portion is formed at a time when the adhesive sheet is applied to the mother seal substrate, thus requiring no processing of the terminal portion afterward. Since the adhesive sheet cut portion extends to reach an edge of the adhesive sheet to prevent deformation of the adhesive sheet around the terminal portion after adhering the mother element substrate and the mother seal substrate with each other under the negative pressure so as to be returned to the atmosphere, thus realizing the solid seal type organic EL display device with high reliability.