PROBLEM TO BE SOLVED: To more easily reconstruct a panoramic image by an imaging system in which an X-ray tube and a detector are independently rotatable, drawing a circular orbit around the same center.SOLUTION: An X-ray tube (21) and a detector (22) are always opposed to each other and a rotation of the X-ray tube and the detector around the same center is independently controlled such that an imaging region is scanned by an X-ray beam with its focus on a reference tomographic plane (SS) determined along the imaging region. An opening size of a slit (23) is controlled according to a fixed distance predetermined within a change width of a distance from the X-ray tube to the detector during the scanning or a distance at which the detector is actually positioned in the change width. Frame data output from the detector is collected at a predetermined period. The frame data is mapped to a memory area (M) on the assumption that the detector is virtually disposed at a maximum separation distance (R) from the X-ray tube. A panoramic image of a tomographic plane of a jaw part is reconstructed on the basis of the mapped frame data.
