Selection with alignment marks of an optimal template, its identification and similarity judgment are conducted by a calculation function of a correlation value provided to a foreign matter inspection apparatus. In other words, the foreign matter inspection apparatus includes unit for registering feature points of alignment marks formed on a surface of an inspected object, unit for collecting image data of the alignment marks formed on the surface of the inspected object and a data processor for extracting a feature point from the image data and calculating a correlation value of both feature points, and registers the image data of the alignment mark on the basis of a threshold value of the correlation value.