According to a radiographic apparatus of this invention, parameters obtained on an assumption that an X-ray tube 2 is moved Wd×m, which is an integral multiple of pixel pitch Wd, in a B− direction opposite to B+ direction which is a direction of movement by Y-direction adjust screws of a moving mechanism, are corrected as parameters obtained when X-rays are emitted from the X-ray tube 2 in a state of a grid 6 having been moved Wd×m by the Y-direction adjust screws. This allows only the grid 6 to be moved without moving the X-ray tube 2. Therefore, parameters equivalent to the parameters which should be obtained when the X-ray tube 2 is moved are obtained by moving the grid 6, and position shifting can be reduced.
