Abstract: A Computer Aided Design (CAD) system with a dimension line editing function manages a drawing involving dimension lines and displays the drawing on a display unit connected to a terminal. The system edits the drawing according to a specified one of the dimension lines. The system has a setting unit for interactively setting an objective dimension line through the terminal; a retrieving unit for retrieving, in the drawing, dimension lines that are in parallel with the objective dimension line; and an editing unit for editing drawing data corresponding to the objective and parallel dimension lines according to a change quantity entered for the objective dimension line. The CAD system only asks a user to specify an objective dimension line to be edited as well as a change quantity applied to the dimension line.