PURPOSE: To ionize a substance ranging from a gas to a solid in one vacuum system to make an ion source device compact and to reduce manufacturing cost, and to simplify the axis alignment of ion beams between the ion source device and an accelerator.

CONSTITUTION: A gas ion source 2 which ionizes a gas and a solid ion source 10 which ionizes a solid are arranged in series on the same axis. An ion beam passing path through which ion beams from the upstream ion source 2 are passed is formed in the downstream ion source 10. A switching means which selectively turns on the gas ion source and the solid ion source is installed.