When a grid point that is the object to be mapped is present in a first division region a color of which has lightness equal to or higher than the lightness at the maximum chroma point in the color gamut and has chroma higher than the chroma at that point, the intersection of a straight line connecting the grid point to the maximum chroma point and an achromatic axis is calculated and a point having lightness equal to or higher than the lightness of the intersection is set as the focal color. Then, the intersection of a straight line connecting the object grid point to the focal color and the boundary of color gamut is set as an output color for the grid point. The output colors are prevented from being separated into color on the high and on the low lightness sides with respect to the maximum chroma point.