An electron emitter has an electric field receiving member formed on a substrate, a cathode electrode formed on one surface of the electric field receiving member, and an anode electrode formed on the one surface of the electric field receiving member, with a slit defined between the cathode electrode and the anode electrode. The electric field receiving member is made of a dielectric material. The electron emitter also has a modulation circuit for modulating a pulse signal applied between the cathode electrode and the anode electrode based on a control signal supplied from a controller such as a CPU to control at least an amount of emitted electrons.