Irrespective of the layout, moving path, and moving range of the X-ray source and the detector, a highly precise image is acquired, in a similar manner as an X-ray CT scanner that is capable of acquiring a measured image using a rotation angle of 180 degrees or more. A measured image detected by the detector is converted into a rotationally measured image that is acquired by rotationally moving the X-ray source and the detector along concentric circular paths. Then, the rotationally measured image at every measurement angle is provided with a weight that gives intensity variation equivalent to that of the reconstructed image obtained from the rotationally measured images acquired by the measurement using the rotation angle range of 180 degrees, a reconstruction operation is performed, and a reconstructed image is obtained.
