A solid sealing method of an organic EL display device is provided which effectively prevents influences of moisture and reduces manufacturing cost. A mother sealing sheet (400) and a mother element substrate (100) are adhered with a use of a positioning mark (+). A rectangular portion shown in a dotted line on the mother sealing sheet (400) is a separation line (41). An adhesive member is formed in the separation line (41), and the adhesive member is adhered to a display region (101) formed over the mother element substrate (100). A cut-out is formed at a corner portion and a short side portion of the rectangular separation line (41) and a cut-out and a bridge are formed on the long side portion. Thus, unnecessary portion of the mother sealing sheet can be removed without losing the reliability of adhesion.