At a wire crossover portion, extension wires, which are electrically connected to scanning electrode connecting wires, extend so as to cross over the other scanning electrode circuitous wires without having contact with the other scanning electrode circuitous wires and to be electrically connected to the corresponding scanning electrode circuitous wire. Thus, it is possible to ensure routes for leading out respective scanning electrodes without having contact with other wires, and it is possible to collectively apply a voltage for an aging treatment to the respective routes. Portions, where the extension wires extend so as to cross over, are formed in the same step as a step for forming a cathode layer as the scanning electrodes.