The present invention is intended to efficiently concentrate an electric field and to improve electron emission efficiency in a field emission cathode constituting a flat display device. A field emission cathode constituting a flat display device is constituted to have an electron emission section arranged to face an electron applied surface. At least the electron emission section is formed out of conductive, thin plate-like fine particles. A substance having a work function of 2 to 3 eV is bonded on the surfaces of the thin plate-like fine particles.