PURPOSE: To provide an image quality display device where the convergence or landing of a color CRT display is easily measured and adjusted.

CONSTITUTION: A signal generating circuit 1 for generating a color video signal STS which is supplied to a color image tube 10 to be measured so as to be displayed as a prescribed pattern is provided. A color image-pickup means 2 for image-picking-up the whole part of the pattern which is displayed in the color image tube 10 to be measured is provided. A processing circuit 5 which processes image-pickup outputs R-B from the color image-pickup means 2 and generates a video signal SMN which two-dimensionally graphic-displays the display deviation of the color image tube 10 to be measured in a horizontal scanning direction and the display deviation in the perpendicular scanning direction on a monitor display 6 is provided.