PURPOSE: To improve transmissivity of X-rays in an input window, and reduce the scattering of the X-rays by constituting the input window of amorphous carbon.

CONSTITUTION: An input screen 6 formed by laminating an input plane substrate 3, an input fluorescent plane 4 and a photocathode 5 upon each other is arranged on an input window 1a on the inside of a vacuum container 1. This input window 1a is formed in a cylindrical capped shape by means of an amorphous carbon thin plate. In this image intensifier, for example, when an X-ray image passes through the input window 1a after passing through a material to be inspected, the input fluorescent plane 4 emits, and photoelectrons are generated by means of the photocathode 5. In this image intensifier, since the input window is composed of amorphous carbon, transmissivity of X-rays becomes excellent, so that the transmissivity can be improved largely particularly in a soft X ray area.