PURPOSE: To make it possible to evaluate quantitatively white color shading of a color cathode ray tube by image-picking up two monochrome screens which are projected sequentially through the same colored optical filter, and by comparing the picture data for both screens with each other.

CONSTITUTION: A color television receiver 1 to be inspected receives a monochrome image signal from a test pattern signal generation circuit 4, and projects a monochrome screen. A monochrome picture is image-picked up by a television camera 3 through a monochrome optial fiber 2. The one-frame-period picture data, which are obtained by image-picking up one monochrome screen, are written in a frame memory 7, and the data, which are obtained by image-picking up other monochrome screens, are written in a frame memory 8. The picture data which are stored in the frame memories 7 and 8 are subtracted or divided with each other by an arithmetic circuit 10. A computer 12 evaluates the color shading based on these arithmetic results.