Image processing means comprises image converting means for converting manipulation data inputted by a user with a manual controller or a mouse into an input pattern image, geometric shape judging means for determining a type of an input geometric shape indicated by the input pattern image based on a plurality of geometric shape judging criterion, image appearance displaying means for displaying a symbolic image corresponding to the type of the input geometric shape on the monitor, and image form determining means for determining a form of the symbolic image displayed on the monitor. The image form determining means comprises accuracy calculating means for determining accuracy of the input geometric shape based on the number of deviations from an allowable range of a judging criteria used in judgment for the determined type of the input geometric shape, and modification displaying means for modifying the form of the symbolic image displayed on the monitor based on the accuracy of the input geometric shape.