PURPOSE: To correspond to a color picture information, which is expressed by various color spaces, at a low cost.

CONSTITUTION: A color space conversion table card, which corresponds to a color space expressing the color picture data sent from a host computer 101 and is formed in the fashion of an IC card, is inserted in an IC card slot 3. At the conversion of color spaces, adresses for accessing to the color space conversion table are produced on the basis of the values of the respective color components of the color picture data sent from the host computer 101 so as to access to the card in order to obtain the YMCK data corresponding to the respective color components of the color picture data.