1. A pattern evaluation method causing a computer to perform operations of: acquiring a plurality of examination images obtained in regard to an evaluation target pattern, at least one of the plurality of examination images being different from the other examination images; detecting, by the computer, all edges of the evaluation target pattern in each of the examination images; executing, by the computer, alignment between the evaluation target pattern of the examination images with a sub-pixel accuracy based on the detected edges; superimposing the edges of the aligned pattern to generate a single combined edge; measuring the combined edge; and evaluating the evaluation target pattern based on a result of the measurement.