A correction data acquisition method for an image display device, which is used to display a predetermined image using a plurality of primary colors. An offset image at a black level is displayed at an image display section of the image display device. A multiband offset captured data is acquired by capturing the offset image through filters corresponding to primary colors. Primary color images at predetermined signal levels of the corresponding primary colors are displayed sequentially. A multiband primary color captured data is acquired by capturing the primary color images through the filters for the corresponding primary colors. Primary color scale images are displayed by varying input signal levels of the corresponding primary colors sequentially. Primary color scale captured data is acquired by capturing the primary color scale images sequentially. Calculation is made of the offset correction data on the multiband offset captured data, the multiband primary color captured data and the primary color scale captured data, so as to acquire correction data relating to color shading in the image display device.