PURPOSE: To display the images at a higher speed in a limited color space with reduced deterioration of the picture quality without affecting the picture quality of the displayed images of the displayed background, the colors of various icons and windows or other applications.

CONSTITUTION: A color space calculation part 11 is provided to calculate the partial color spaces to which each color belongs together with a standard color memory 18 which stores the key color or each partial color space as a standard color, a color map 19 where the correspondence is secured between the color spaces having the limited number of colors that can be displayed at one time and the color spaces permitted for display, a key color memory 17 which secures the correspondence between the partial color spaces and the colors assigned to the map 19, a color selecting part 15 which selects the colors approximate to an inputted color, and an image display part 16.