Storage areas for storing four types of correction data tables for each color, which are configured by data to which gradation level data of a color is corrected, are provided as RAM1 to RAM4. A first selector selects three types of correction data tables, from which correction data for gradation level data of each of three primary colors of a color image is to be obtained, from among the correction data tables stored in the RAM1 to the RAM4. A second selector obtains correction data for gradation level data of each of the three primary colors from the correction data tables selected by the first selector. A CPU makes a RAM other than RAMs storing the correction data tables selected by the first selector among the RAM1 to the RAM4 store a correction data table, which is configured by data to which the correction data is changed.