PURPOSE: To permit easy visual controlling of set data by providing a data exposure means for imprinting of photographing data in a cassette device.

CONSTITUTION: When X-rays are radiated from an X-ray generating part 3 by emitting a signal from an X-ray control part 2, the signal from the part 2 acts as a trigger; at the same time, an exposure on-off control part 8 goes on. The data started in a specified format are called out from a data setter 10 to a light emitting device 7 by an exposure control part 9, and the data are transmitted to an exposure device 18 through a fiber cable 12 as a light signal. Thus in the case of subjecting an object 4 to be examined to X-ray photographing, the data light signal is received partially by the device 18, and the film is exposed, whereby the required data are imprinted thereon.