PURPOSE: To provide a deflection yoke adjustment device in which a deflection yoke is adjusted automatically efficiently with high precision.

CONSTITUTION: A prescribed pattern is displayed on a screen of a reference cathode ray tube 2 to which a deflection yoke 1 to be adjusted is mounted by a video image pattern signal generated from a pattern generating circuit 31 of a drive section 3, an image pickup signal obtained by picking up an image of the screen of the reference cathode ray tube 2 by an image pickup section 4 is stored in image memories 52R, 52G, 52B of an image processing section 5, a central processing unit 53 analyzes the image pickup signal to calculate mis-convergence and image distortion to control the operation of a vertical deflection coil adjustment mechanism section 7 moving the vertical deflection coil of the deflection yoke 7 in the horizontal axial direction, the vertical axial direction and in the axial direction around a center axis.