PURPOSE: To provide an X-ray radioscopy photographing device which can improve the operation performance of a diaphragm or mask and can effectively utilize an X-ray film.

CONSTITUTION: An X-ray radioscopy photographing device is equipped with a control means consisting of an input part 31 which can receive a desired region among the X-ray radioscopic images displayed on an X-ray TV means 23 and a calculation part 32 which drive-controls an X-ray cut-off means 24 so that only a desired input region is formed on an X-ray sensing means 3 and drive-controls the X-ray sensing means 3 so that the desired region is formed at a prescribed position on the X-ray sensing means 3. The calculation part 32 calculates the projection size in the desired region on the arrangement surface of the X-ray cut-off means 24, and the X-ray cut-off means 24 is constituted so as to be driven, so that the opened port size of the X-ray cut-off means 24 neaaly accords with the projection size.