A design support apparatus displays components of a design object on a display screen in the same positional relationship as that of actual layout, and graphically displays an installation inhibit area for the components which is derived from the design object or its components, on the display scree. An operator may design the layout while he/she looks as the display screen to designate installation position of the components so that they do not enter into the installation inhibit area. The installation inhibit area displayed on the screen may be a minimal space from a wall of the component or a working space for the component.