To provide an X-ray filter that can prevent the rupture of an X-ray transmission aperture of a member provided with the X-ray transmission aperture to which converging X-rays are radiated.

An X-ray filter is arranged on the X-ray radiation side of a member 32 provided with an X-ray transmission aperture to which converging X-rays are radiated, in a state of being isolated from the member 32. This X-ray filter is provided with an X-ray transmission film of the same material as the X-ray transmission aperture of the member 32 or an X-ray transmission film with an X-ray absorbing characteristic equal or approximate to the X-ray transmission aperture of the member 32, and arranged in a position where the X-rays are radiated at a lower convergence degree than the X-rays radiated to the X-ray transmission aperture of the member 32.