A monocoque-structured housing accommodates a photoelectric conversion panel, a scintillator, and a circuit board in this order from an X-ray incidence side. The scintillator contains cesium iodide and converts X-rays into visible light. The scintillator is vapor-deposited on the photoelectric conversion panel. A plurality of pixels that photoelectrically convert the visible light into charges are formed in the photoelectric conversion panel. A signal processor, which reads out the charge from each pixel and generates image data, is mounted on the circuit board. A gap layer is formed between the scintillator and the circuit board.
