To provide an organic EL panel of superior durability in which airtight space can be retained even if under a severe environment.

This panel is provided with lamination treatment in which an organic EL element 10 consisting of at least transparent electrode 2, an organic layer 4, and a rear face electrode 5 on the glass substrate 1 is laminated on the glass substrate 1, with sealing treatment in which the organic EL element 10 is sealed by adhering a sealing member 6 on the glass substrate 1, and with plasma surface treatment which is carried out until the sealing treatment is carried out after the lamination treatment is carried out and cleaning of the adhered place of the sealing member 6 in the glass substrate 1 is carried out.