To provide an X-ray radioscopic photographing apparatus including an FPD capable of moving inside the apparatus and attachable/detachable to/from the apparatus.

A snapshot part 5 has a box-shaped envelope container surrounding all sides of a base plate 52 with side walls, and one side face thereof is formed with a take-out port 51 through which the FPD 54 can be attached/detached to/from the snapshot part 5. A tray 53 for placing the X-ray photographing FPD 54 and a roller 61 around which a cable 55 of the FPD 54 is wound and which supports it are disposed on the base plate 52. The tray 53 is disposed with a roller 62 and a roller 63, and a guide groove 57 movably fitted on a guide roller 64 energized by a spring 56 is formed between the roller 62 and the roller 63. A guide member 70 opened/closed and deformed by a hinge is disposed between the roller 61 and the roller 62 in a state of supporting the cable 55.