An image forming device, which is capable of double-side printing to form an image on each of first and second sides of a recording medium, includes a calibration unit configured to perform calibration for modifying quality of the image to be formed, a first judging unit configured to judge, for each page to be printed, whether the calibration is to be performed, a second judging unit configured to judge whether a page to be printed is one of a first side in one-side printing and a first side in the double-side printing, and a control unit configured to control the calibration unit to perform the calibration when the first judging unit judges that the calibration is to be performed, and the second judging unit judges that the page to be printed is one of the first side in the one-side printing and the first side in the double-side printing.