1. A position measuring apparatus comprising: a first irradiating part that irradiates a first beam to an object; a second irradiating part that irradiates a second beam to the object; a capturing part that captures images of the object; a processing part that generates a first difference image and a second difference image by processing the images captured by the capturing part; an extracting part that extracts a contour and a feature point of the object from the first difference image; a calculating part that calculates three-dimensional coordinates of a reflection point located on the object based on the second difference image; and a determining part that determines a position of the object by matching the contour, the feature point, and the three-dimensional coordinates with respect to predetermined modeled data of the object.