An ion pump and a charged particle beam device each includes two opposite flat-plate cathodes, an anode with a cylindrical shape having openings that face the respective flat-plate cathodes, a voltage application unit configured to apply a potential higher than potentials of the flat-plate cathodes to the anode, a magnetic field application unit configured to apply a magnetic field along an axial direction of the cylindrical shape of the anode, and a cathode bar arranged within the anode. The surface of the cathode bar is formed with a material that forms a non-evaporative getter alloy film on the anode or the flat-plate cathodes.