When performing an offset correction, without lowering an image quality of the radiographed image data, a prompt radiographing is realized. Hence, a memory 105 stores a first image data for offset correction generated by performing an interlace scanning of the driving lines of odd rows only in a driving circuit unit 103. A memory 106 stores a second image data for offset correction generated by performing the interlace scanning of the driving lines of even row only in the driving circuit unit 103. A processing unit 108 synthesizes the first image data for offset correction and the second image data for offset correction, thereby to generate an image data for offset correction of one frame portion, and an arithmetic operation unit 109 performs an arithmetic operation processing on the radiation image data stored in a memory 107 by using the image data for offset correction of one frame portion synthesized and generated, thereby to perform the offset correction of the radiation image data.