Provided is a machine and a method for inspecting an input shaft of a power system. First an second cameras take a photograph of first and second champer of the input shaft from directions perpendicular to the chamfers to capture image data of the chamfers. The input shaft is rotated by an indexing drive until overlapping a central line of first and second chamfers of an input shaft on a standard line of image array coordinate system of a computer. Then, widths of the first and second chamfers of the input shaft is calculated. Thereafter, the indexing drive rotates the input shaft by predetermined degrees. The computer processes image data of another first and second chamfers captured by the first and second cameras and calculates widths of the another first and second chamfers. Continuously, widths of remaining chamfers of the input shaft are calculated.