X-RAY MEASURING INSTRUMENT

PROBLEM TO BE SOLVED : To provide a three-dimensional X-ray measuring instrument enabling a good measurement with respect to a subject having a high X-ray absorber. SOLUTION : This X-ray measuring instrument has a means for performing a first reconstitution processing (104) using projection data (103), a means (106) for carrying out an extraction processing of a value larger than a threshold value in reconstitution data (105), a means (107) for performing a re-projection processing (108) of a re-projection data from the extracted reconstitution data, a means (109) for subjecting the re-projection data (108) to a secondary conversion processing, a means for multiplying the secondarily converted re-projection data (110) by a weight coefficient, a means (111) for subjecting the weighted re-projection data to a differential processing from the projection data, and a means for performing a second reconstitution processing (113) using the differential re-projection data (112).