An SED is formed by sealing a front-side substrate provided with an image display area having a fluorescent layer on its inside surface, and a back-side substrate provided with a plurality of electron-emitting elements and driving wires for driving the electron-emitting elements, through a rectangular frame-like sidewall. On the outside of the image display area of the front-side substrate, frame-like power supply wiring to apply a high voltage to the image display area through a metal back is formed. In the area of the back-side substrate opposite to the power supply wiring, a bypass member to function as a lightning rod is provided electrically independent of a lower wire.