PURPOSE: To change color even when the color of object image 15 the same as the illumination light and the two-dimensional reflection light and an object reflection model cannot be specified by changing the color of the object picture according to the object reflection model.

CONSTITUTION: The device is provided with a judgement means 16 judging whether or not the object color vector specified for the calculation of the parameter of the object reflection model is almost the same as the illumination light vector or the two-dimensional reflection light vector and calculation means 20 calculating the color data after changing the color of each picture element of the object picture based on the object color vector being the condition of changing colors and the color data before changing the color of each picture element of the object picture, and the characteristic color data specified relating to the color data when the judgement means 16 judges the same color. The judgement means 16 judges the same color, the color display processing of the object picture is performed according to the color data calculated by the calculation means 20.