PROBLEM TO BE SOLVED: To highly accurately measure a shape and a dimension.
SOLUTION: At the time of measuring an object W to be measured, an image is picked up by a digital camera such as a CCD camera and measurement points 1-6 are extracted from an obtained picked-up image. When the measurement points 1-6 are extracted from the size of the pixel Pij of the picked-up image, the coordinate values (x1-x6, y1-y6) of the respective measurement points 1-6 are computed. Since an aberration is included in a lens system on a reproducing picked-up image, distortion aberration correction is executed to the coordinate values (x1 to x6, y1 to y6) of the respective measurement points 1-6. The distortion correction is executed by performing approximation by a preset multi-dimensional polynomial correction formula.