With chemically-strengthened thin glass substrates provided with an alkali barrier film, if the light-absorbing or light-scattering nature of the alkali barrier film itself has lowered the light extraction efficiency, or if the surface of the alkali barrier film is insufficiently flat, there may consequently be an increase in leakage current of an organic EL element and a decrease in reliability, leaving room for improvement. Instead of such an alkali barrier film, by providing an organic EL panel with a barrier film of the present invention and also with an organic EL element on a chemically-strengthened thin glass substrate with a specific light extraction structure therebetween, the glass substrate having one principal surface that includes a smooth region of the present invention, a high-performance organic EL panel can be obtained without compromising the organic EL properties.