Abstract: An X-ray image intensifier photofluorography apparatus for correcting the output image brightness while photographing an optical image of a subject in an optical camera through a lens system by amplified light into which X-rays are converted after passing from an X-ray source through the subject to an X-ray image intensifier, wherein filter means whose X-ray permeability is represented by an axially asymmetric form relative to the central horizontal axis between the X-ray source and X-ray image intensifier to correct the distribution of the intensity of X-rays emitted from the X-ray source. The X-ray permeability of the filter means is adjusted by changing a length of X-ray path or the thickness of the filter means through which X-rays are transmitted.