An image acquiring section acquires a pattern image of a sample. A figure creating section creates a figure, which reflects a shape of the micropattern, on the basis of the pattern image. A density distribution data acquiring section acquires density distribution data on a straight line perpendicular to a tangential line of an outline of the figure. An edge detecting section detects pattern edge coordinates from the density distribution data. A pattern shape measuring section measures a shape of the micropattern on the basis of the pattern edge coordinates.