Color shift correction comprising: (a) imaging an object and acquiring image data of each of a plurality of color planes including planes of primaries; (b) determining whether a color of each of pixels of color image data obtained by combining the image data of each of the plurality of color planes is imaginary; (c) counting the number of pixels determined in step (b) to have imaginary color and calculating the number of pixels within one frame which have imaginary color; (d) repeating a process of performing a pixel shift operation, relative to image data of each of the plurality of color planes, and performing steps (b) and (c) using the image data of each of the plurality of color planes having undergone the pixel shift operation, and obtaining, a pixel shift operation for the color planes; and (e) correcting the image data of the plurality of color planes on the basis of the pixel shift operation.