PROBLEM TO BE SOLVED: To solve the problem that in standard gauges for accurately calibrating the dimension of a shape including the internal shape of a sample from a projection image obtained from an X-ray CT scanner, a standard gauge formed corresponding to the shape, etc., of the sample may not be appropriately checked by a three-dimensional measuring machine.SOLUTION: The calibrator of an X-ray CT scanner capable of measuring the dimension of each part by a contact type three-dimensional measuring machine if always needed is provided using a calibrator having a structure arranged by a plurality of balls having different outer diameters in the outer circumference of a cylindrical body or a column body.
