PROBLEM TO BE SOLVED: To perform accurate offset correction, and to more improve a frame rate than a conventional manner.SOLUTION: A first offset value calculation section 35 calculates a first offset value on the basis of a beyond-photographic time dark image photographed beyond the photographic time of an X-ray image by a dark image photographing section 32. A second offset value calculation section 36 calculates a second offset value on the basis of a within-photographic time dark image photographed within the photographic time of an X-ray image by the dark image photographing section 32. Then, an offset correction section 37 performs the offset correction of an X-ray image photographed by an X-ray image photographing section 31 by using the first and second offset values. In this case, a storage time setting section 34 sets the storage time of charge related to the within-photographic time dark image shorter than that of charge related to the X-ray image.
