US Patent 10115557 X-ray generation device having multiple metal target members

An X-ray generation device which can be efficiently used is provided. The X-ray generation device has an electron gun, a target unit, a tubular portion, a reflected electron detector, and a coil unit. The target unit includes a plurality of targets and a plurality of mark portions having a predetermined relationship with the targets, wherein each mark portion having a surface area larger than a surface area of the target when said target unit is viewed from a direction which is normal to principal faces of the target unit.