The device includes a hue compensator converting hue of input signals having a first color gamut representing image data to hue conversion signals, a gamut converter outputting the input signals as gamut conversion signals having a second color gamut to display the input signals on an image display device representing the second color gamut, a blend coefficient setter that sets a blend coefficient defining a synthesis ratio of the hue conversion signals and the gamut conversion signals based on saturation obtained from the input signals, and a color synthesizer that generates synthesized image signals by synthesizing the hue conversion signals and the gamut conversion signals at a ratio according to the blend coefficient. The gamut converter performs conversion such that a value of each component of the hue conversion signals is from 0 to 1 when a value of each component of the input signals is from 0 to 1.