In an image processing apparatus of the present invention, a chromaticity data converting device converts chromaticity data of an original image into chromaticity data which can be outputted from an image output device based on chromaticity data obtained from a color signal of a color sample stored in a first storage device and chromaticity data obtained from a color signal of an input image stored in an original data storage device. Then, a second color converting device converts the chromaticity data converted by the chromaticity data converting device into a signal which can be outputted from the image output device based on data stored in a third storage device. As a result, the chromaticity data of a color signal is converted for each input image individually, thereby making it possible to reproduce colors faithfully to the original image.