Abstract: A display device displaying a plurality of information sets with a simple structure, and a keyboard instrument that has a key guide device including such a display device. The display is driven at cycles shorter than those discernible by human beings, and the time ratio of ON period to OFF period for the display is changed based on control data. More specifically, the ON state and OFF state are inverted each drive cycle, or the number of cycles during which the display is in ON or OFF state can selected, or the drive cycles are cyclically changed to turn ON the display means only in a designated cycle. In this manner, the luminance of and the hues of the display can be changed relative to the continuous lighting, and a plurality of information sets can be displayed based on this change. This display device may be employed as a fingering guide display device for a keyboard instrument, and position data for keys to be depressed and other playing guide information are displayed at the same time.