Abstract: An electron tube is constructed to seal in vacuum a substrate for supporting an electron collect electrode, a substrate for supporting a cold cathode array, and a part of an electrode structure. Electrons, emitted from an electron discharge area composed of the cold cathode array and the electrode for picking up an electron beam, pass through a vacuum area and reach an electron collect electrode. The vacuum area is formed by anode jointing the outer peripheral portion of the substrate 1 for supporting the electron collect electrode with the part of the electrode for picking up an electron beam in a vacuum bath. After sealing them in vacuum, the vacuum level of the vacuum area can be kept unchanged when the electron tube is taken out of the vacuum vessel.