In accordance with an aspect of the present invention, a color display device (10) includes a plurality of gas discharge tubes disposed side by side. The gas discharge tubes have respective phosphor layers (4R, 4G, 4B) of different materials for different colors disposed therein and containing discharge gas therein. Each of the gas discharge tubes has a plurality of light-emitting points disposed along the length thereof. The color display device further includes a plurality of display electrodes disposed on the display screen side of the gas discharge tubes, and a plurality of signal electrodes (3) disposed on the rear side of the gas discharge tubes. Voltage control layers (6R, 6G, 6B) are disposed between the phosphor layers and the signal electrodes. The voltage control layers are made of materials which change firing voltages applied between the display electrodes and the signal electrodes. The materials of the voltage control layers are selected for the different materials of the different phosphor layers so as to minimize the difference of the firing voltages for the plurality of gas discharge tubes.