To provide an electron source structure capable of stably extracting a minute beam for a long period by stably holding an electron emission cathode, and to provide an electron source structure drive device.

The electron source structure includes at least: the electron emission cathode formed of diamond; a pair of conductive posts holding the electron emission cathode; a metal screw and a nut for generating stress for holding the electron emission cathode by penetrating the conductive post; an insulating insulator for keeping electrically insulation between the metal screw and nut, and the conductive post by being penetrated by the metal screw and the nut; a pair of electrode terminals for fixing the conductive post; and an insulator equipped with the terminals.