PURPOSE: To execute the compensation of a video signal in real time by calculating the size relationship between mutual data of respective colors of red, green, and blue, adding a compensation data inputted from the outside to the maximum chrominance signal, and deriving a color compensation signal.

CONSTITUTION: First, the analog signals of a red color R, green color G, and a blue color B are digitalized at A/D conversion circuits 1a-1c. Next, at comparators 2a-2c, a calculation processing to obtain the size relationship between the mutual data of respective colors R, G, and B is executed. The maximum chrominance signal is obtained at a calculation and logic circuit 3 based on this result, and the signal is supplied through data selectors 5d-5e to adders 5a-5c. On the other hand, data A, B, C for compensation from the outside is written into a data register 4 by a data input control signal. And, compensation data corresponding to the above maximum chrominance signal is added by the adders 5a-5c, and the color compensation signal is derived. This circuit is made of a combination of simple standard ICs, and the compensation of the video signal can be executed in real time.