Disclosed is an image processing device including: a sample output unit to instruct a print device to successively print test images on a plurality of sheets of the recording paper; a profile preparing unit to prepare a plurality of profiles of the density unevenness in the sub-scanning direction in the plurality of sheets of the recording paper, from measuring data obtained by optically reading the test images; an analyzing unit to analyze the profiles by arranging the profiles in a printing order apart from each other so as to correspond to intervals of the sheets of the recording paper, and to detect a long period density unevenness in the sub-scanning direction, which has a long period extending through the plurality of sheets of the recording paper; and a correction data preparing unit to prepare correction data for removing the long period density unevenness.