PURPOSE: To attain a high precise color conversion by a simple color correction arithmetic operation by providing a mechanism which switches the coefficient of the conversion arithmetic operation according to the upper bits of the signal values of R, G, and B signals, and a mechanism which operates the conversion arithmetic operation.

CONSTITUTION: The color conversion arithmetic operation of the three decomposition data R, G, and B of a color picture is performed, and color converted output signals R', G', and B' are outputted. This device is equipped with a mechanism 2 which switches the coefficient of the conversion arithmetic operation according to the upper bits 8 of the signal values of the R, G, and B signals, and a mechanism 1 which operates the conversion arithmetic operation. Now, the three analytic data R, G, and B of color picture are used as 8 bit digital data, the color correction arithmetic operation is operated by the conversion arithmetic mechanism 1 based on the R, G, and B data, and a correction coefficient matrix, and the corrected 8 bit data R', G', and B' are outputted. The value of the element of the correction coefficient matrix is not fixed, and switched by the conversion coefficient switching mechanism 2. The mechanism 2 inputs the upper 2 bits 8 of the R, G, and B data, and outputs a correction coefficient 9 of 64 patterns.