An image-correction method is realized, in which, by utilizing a table having small storage area, high-accuracy shading correction can be implemented, that does not undergo deterioration of performance, even when shading properties dynamically change.An image-correction method according to the present invention includes a distance calculating step of calculating the distance between the coordinates of an image-constituting pixel and predetermined reference coordinates, a distance-correction value calculating step of calculating a distance-correction value, by inputting for the variable in an N-order function (N being a positive integer) the distance that has been calculated in the distance calculating step, a correction coefficient calculating step of calculating, based on a table that represents correspondences between distance-correction values and correction coefficients, a correction coefficient corresponding to the distance-correction value that has been calculated in the distance-correction value calculating step, and a pixel signal correcting step of correcting a signal for the pixel, based on the correction coefficient that has been calculated in the correction coefficient calculating step.