1. An X-ray image intensifier photofluorography apparatus for emitting X-rays from an X-ray source through a subject to an X-ray image intensifier, converting the X-rays into amplified light, photographing the light image through a lens system in an optical camera, and correcting the brightness of the output image, wherein X-ray distribution-correcting filter means whose X-ray permeability is represented by an axially asymmetric form relative to the horizontal axis is disposed between the X-ray source and X-ray image intensifier.