Abstract: An electron discharge device characterized in having a conductive layer on one surface of a dielectric substrate, a dielectric layer and a conductive layer, in this order, on the other surface of the substrate, wherein the dielectric layer has a thickness equal to or less than 5 nm and a permittivity lower than that of the dielectric substrate. A method for discharging electrons from a surface of a conductive layer (2) by applying voltage between conductive layers (1) and (2) of a device having the conductive layer (1) on one surface of a dielectric substrate, a dielectric layer and the conductive layer (2), in this order, on the other surface of the substrate, wherein the dielectric layer has a thickness equal to or less than 5 nm and a permittivity lower than that of the dielectric substrate, such that a conductive layer (1) serves as a cathode and that the conductive layer (2) serves as an anode.