A field emission cold cathode sends forth uniform emission over the entire emission area and realizes, when applied to a flat screen display device and the like, a uniform brightness of images over the entire display area, providing a high quality field emission type cold cathode. An electron tube is equipped with the cold cathode. The cold cathodes structurally prevent a prolonged electric discharge with the use of trenches. Non-uniformity of resistance, resulting from the difference in extension of the depletion regions in each block divided by the trenches, can be prevented by an arrangement of blocks in which each block divided by trenches is placed to have a prescribed distance from an adjacent block, which makes emission currents in all blocks within the formed emitter area uniform at the time of normal operation, and thereby a good form in which depressions in the block corner sections are well suppressed can be obtained.