To achieve a low-cost X-ray detector that is excellent in the photo-transfer characteristics from a scintillator to a photodetector, and a method for manufacturing such an X-ray detector.

The X-ray detector for detecting X rays includes a photodetector (52b) and a scintillator layer (52a) consisting of a fluorescent material coating a light-receiving face of the photodetector for converting the X ray into the light. The fluorescent material is rare-earth oxysulfide. The rare-earth oxysulfide is oxysulfide gadolinium (Gd2O2S:Tb). The photodetector has a photodiode array on the light-receiving face. The photodiode array is a two-dimensional array.