In a field emission electron gun including emitters (104) on predetermined parts of a substrate (109), an insulator film (105) on a remaining part of the substrate, a first gate electrode (101) on the insulator film so as to surround the emitters with a space left between each emitter and the first gate electrode and to have an outer peripheral surface defining an emission region (E), a gate edge portion (106) of a conductor is formed on the insulator film to surround the outer peripheral surface of the first gate electrode in contact with the outer peripheral surface of the first gate electrode. A second gate electrode (102) is formed on the insulator film to surround the gate edge portion with a distance left between the gate edge portion and the second gate electrode applied with a second voltage less than a first voltage applied to the first gate electrode.