Disclosed is an X-ray imaging device, which is capable of providing a tomographic image of an image layer disposed between an axis of rotation and an X-ray source. The imaging device according to the present invention includes a radiography unit having an X-ray source and an X-ray sensor disposed to face each other with a rotating axis therebetween, wherein the X-ray sensor configured to obtain X-ray transmission images, a driver configured to rotate the X-ray source and the X-ray sensor about the rotating axis, and an image processor configured to provide a two-dimensional tomographic image of an image layer disposed between the rotating axis and the X-ray source, by shifting and overlapping the X-ray transmission images after reversing left and right at least some of the X-ray transmission images.