A color adjusting apparatus comprising: a first storage unit configured to store information indicating a hue range arbitrarily designated in a hue space; a second storage unit configured to store an adjustment value for adjusting a degree of color shift in the hue range; and a color conversion unit configured to perform a color space conversion from a color space defined by red, green and blue, so to generate an input image data that is in a color space defined by hue, saturation and lightness, and to execute a color conversion, wherein the color conversion is expansion processing or compression processing on a color component of the input image data, the color component being associated with the hue range, in accordance with the degree of color shift determined by the adjustment value, wherein the input image data on which the color conversion unit performs the color conversion has undergone the color space conversion so that the input image data is in a color space defined by hue, saturation, and lightness characterized in that the expansion processing is executed by decreasing the rate of increase of the color component according to a first non-linear differentiable function in a first sub-range, while the rate of increase of the color component in a different contiguous sub-range is increased according to the first non-linear differentiable function and the compression processing is executed by increasing the rate of increase of the color component according to a second non-linear differentiable function in a first sub-range, while the rate of increase of the color component in a different contiguous sub-range is decreased according to the second non-linear differentiable function. a first storage unit configured to store information indicating a hue range arbitrarily designated in a hue space; a second storage unit configured to store an adjustment value for adjusting a degree of color shift in the hue range; and a color conversion unit configured to perform a color space conversion from a color space defined by red, green and blue, so to generate an input image data that is in a color space defined by hue, saturation and lightness, and to execute a color conversion, wherein the color conversion is expansion processing or compression processing on a color component of the input image data, the color component being associated with the hue range, in accordance with the degree of color shift determined by the adjustment value, wherein the input image data on which the color conversion unit performs the color conversion has undergone the color space conversion so that the input image data is in a color space defined by hue, saturation, and lightness characterized in that the expansion processing is executed by decreasing the rate of increase of the color component according to a first non-linear differentiable function in a first sub-range, while the rate of increase of the color component in a different contiguous sub-range is increased according to the first non-linear differentiable function and the compression processing is executed by increasing the rate of increase of the color component according to a second non-linear differentiable function in a first sub-range, while the rate of increase of the color component in a different contiguous sub-range is decreased according to the second non-linear differentiable function.