When an input color signal of a first color space is converted to a color signal of a second color space having a color reproduction range narrower than that of the first color space, it is determined whether a color signal that is outside the color reproduction range of the second color space having the color reproduction range narrower than that of the first color space exists within the input color signal of the first color space. If it has been determined that a color signal outside the color reproduction range of the second color space exists, the hue system of the color signal represented in the first color space is converted to the hue system of the color signal represented in the second color space having the narrower color reproduction range.