1. An X-ray tomographic imaging apparatus, comprising: a data acquiring device comprising: an X-ray tube radiating X-rays whose intensities are dependent on an amount of current to be supplied thereto; a detector provided with a detection section in which a plurality of pixels are arranged two-dimensionally, the pixels detecting the incoming X-rays and outputting, frame by frame, digital electric data; support means having the capability to provide a curved orbit and support the X-ray tube and the detector such that the X-ray tube and the detector are movable along the orbit independently of each other, moving means having the capability to move the X-ray tube and the detector along the orbit independently of each other such that the X-rays are transmitted through an object being imaged, at desired angles and at respective positions in a scanning direction of a desired tomographic plane of the object, wherein the object is located inside the orbit provided by the data acquiring device; panoramic image procuring means having the capability to apply a tomosynthesis technique to the data acquired by the data acquiring device to produce a panoramic image of the tomographic plane based on the data; and tomographic image producing means having the capability to produce a tomographic image based on the data acquired by the data acquiring device and the panoramic image produced by the panoramic image producing means, structural components existing in the object being optimally focused in the tomographic image and distortions due to differences in angles of paths of the X-rays being suppressed in the tomographic image.