A dimension measuring apparatus for measuring a dimension between a first data contour which is an evaluation reference of a pattern to be evaluated and a second data contour which is the pattern to be evaluated generates first correspondence information between a point on the first data contour and a point on the second data contour, determines consistency of a correspondence included in the first correspondence information, corrects an inconsistent correspondence, and generates second correspondence information, when associating a point on the first contour data and a point on the second contour data with each other.