ION GUN AND ION MILLING MACHINE

Provided is an ion gun that is capable of obtaining a higher plasma efficiency. This ion gun comprises: a first cathode 21 that is formed in a disc shape; a second cathode 12 that is formed in a disc shape and has an ion beam extraction hole 101a provided thereto; a first permanent magnet 14 that is disposed between the first cathode and the second cathode, and that is formed in a cylindrical shape; an anode 23 that has a cylindrical region 35a and an extending region 25a provided to one end of the cylindrical region; and an insulating material 26 that keeps the anode electrically insulated from the first cathode, the second cathode, and the first permanent magnet, all of which are electrically connected. The cylindrical region of the anode is disposed inside the inner diametrical position of the first permanent magnet, and the extending region of the anode is disposed so as to cross over the inner diametrical position of the first permanent magnet and to face the first cathode.