A wiring structure, a substrate for a display device provided therewith and a display device. The display device features a high brightness and a good display quality. The display device comprises a plurality of pixel regions arranged on a glass substrate; a TFT arranged for each of the pixel regions; an organic EL element including an anode formed by using an ITO for each of the pixel regions, and electrically connected to the source electrode of the TFT, an organic EL layer formed on the anode, and a cathode formed on the organic EL layer to transmit light from the organic EL layer; and a reflection plate for reflecting light from the organic EL layer.