An electron emitter has an emitter made of a dielectric material and an
upper electrode and a lower electrode for being supplied with a drive
voltage for emitting electrons. The upper electrode is disposed on an
upper surface of the emitter, and the lower electrode is disposed on a
lower surface of the emitter. The upper electrode has a plurality of
through regions through which the emitter is exposed. Each of the through
regions of the upper electrode has a peripheral portion having a surface
facing the emitter and spaced from the emitter.