The present invention provide an outline extracting apparatus, a method for extracting an outline, a computer readable memory medium stored with an outline extracting program and a computer readable memory medium stored with an outline data which can exactly extract the outline less influenced by the dispersion of the non-contact point group data and also can exactly extract the outline of a corner having an acute angle. The present invention is characterized in that it comprises an extracted origin data memory module for storing the CAD data and the non-contact measuring point data previously aligned with the CAD data; an analytic surface extracting module for extracting an analytic surface having a predetermined configuration from the CAD data; a surface generating module for carrying out the surface generation using the analytic surface and the non-contact measuring point data; and a crossing line extracting module for extracting a crossing line of surfaces generated by the surface generating module as the outline.