A position detection apparatus for detecting a position of a mark on an object
includes a camera which captures an image of the mark, an extraction section which
extracts a plurality of edge positions of the mark based on a signal derived from
the image of the mark, each of the edge positions being associated with a combination
of a direction and a polarity of the signal, and a determination section which
determines a position of the mark, by comparing each of the plurality of extracted
edge positions with a corresponding one of templates prepared for the respective combinations.
