PURPOSE: To provide a picture correcting device in which each kind of correction of convergence, geometrical distortion, luminance, and focus or the like can be automatically attained, in a device which corrects a color television receiver.

CONSTITUTION: This device is equipped with a test signal generating part 5 which generates a test signal whose maximum value is positioned in the same direction as each scanning direction to a display screen 13 of a picture display device 1, image pickup part 2 which image-picks up the display screen 13, position and level detecting part 3 which detects a centroid position and a level from a photoelectric conversion signal in which the inclination of an image pickup signal is lineally changed, error calculating part 4 which calculates the error value of each color from the detection signal, and correction signal preparing part 6 which prepares a correction signal for correcting the convergence, geometrical distortion, luminance, and focus from the calculation signal. Thus, the picture display device 1 can be driven by the corrected waveform, and each kind of correction can be automatically attained.