A method of generating a correction value of an image display device having an image display unit and a correction unit, the image display unit having a screen on which an image is displayed and an image generating device which is paired with the screen and of which an output characteristic value has distribution and the correction unit correcting an inputted image signal by using a correction value corresponding to the distribution of the output characteristic value and then outputting the corrected image signal to the image display unit, includes: detecting the distribution of the output characteristic value of the image displayed on the screen; setting nodes within corresponding output characteristic distribution on the basis of the detected output characteristic distribution; dividing the image into a plurality of element regions by connecting the set nodes to one another; and setting a correction value for each of the divided element regions.