1. A color conversion apparatus comprising: a color conversion table for receiving input image data represented by a first color space to output color-converted data represented by a second color space, said color-converted data corresponding to lattice points of a lattice component containing the input image data in said first color space; interpolation processing means for performing interpolation processing using the color-converted data output from said color conversion table; and a switching unit for changing lattice points corresponding to the color-converted data to be used by said interpolation processing means, according to position of said input image data in said first color space.