An electronic display device that allows the hierarchy or system to which the display screen belongs to be easily identified, without narrowing the display area of a plurality of screens constituting a director structure. In the display device, a plurality of key input screens form a director structure in association with each other. The directory structure includes first to fourth hierarchy levels. Respective key input screens are located at any of the hierarchy. Upon depression of a transition key in a basic screen belonging to the first hierarchy, the display screen is switched to one of key input screens belonging to the second hierarchy. The display device changes the display color according to the hierarchy to which the key input screen belongs in providing a display of a key input screen.