A navigation system for easily determining defective positions is provided. In the case of CAD navigation to defective positions, logical information for indicating defective positions is created in a CAD format, instead of CAD data of physical information indicating circuit design. Specifically, by attaching marks such as rectangles, characters, or lines, to an electron microscope image with software, quick navigation is performed with required minimum information. By using created CAD data, re-navigation with the same equipment and CAD navigation to heterogeneous equipment are performed.