1. An image forming apparatus being able to print to an index paper, comprising: an index label information setting part that sets up index label information; an index label preview display part that displays a preview of an index label by the index label information; and a shift image display part that displays a shift image, a text printed to a standard size section and an index label section is set to a manuscript, and image area of the manuscript is moved in case of printing the text of the manuscript to the index label.