This image processor 10 includes: an input interface 11 that receives first and second images, on one of which the position of the subject has shifted in a particular direction from the position on the other; a color image generating section 13a that generates a color image in which the pixel values of respective pixels of the first and second images are used as the values of first and second colors, respectively; a decision section 13b that calculates an index value indicating the degree of color shift between the first and second colors in the color image and that determines, based on the index value, whether or not the first and second images match each other; and an image moving section 13c that performs, if the decision has been made that the first and second images do not match each other, the processing of making the second image closer to the first image by replacing the pixel value of each pixel of the second image with the pixel value of a pixel that is adjacent to the former pixel in the particular direction.