To obtain a cathode electrode (a cathode structure) where the electron beam spot diameter or size is reduced, the cathode driving voltage is lowered and the cathode current is stabilized for a long period, a recess or a region which does not radiate electron beams is formed near the central portion or near the outer circumference portion of an electrode radiation substance 9 of a cathode electrode 1, and hollow electron beams are obtained related to a cathode electrode, its manufacturing method, an electron gun and a cathode-ray tube.