To provide a preview image generating method for enabling a user to easily understand the layout of pages and therefore for avoiding spending a large amount of time when displaying the finished state of print pages.

An image forming apparatus with a preview function is provided with: an image processing part for generating the image of a finished state of print pages; an area determining part for dividing the image into one or more areas based on a plurality of predetermined image features to determine the arrangement of the divided areas; a symbol data storing part for previously storing symbols for preview display predetermined in accordance with the respective image features; a preview image generating part for generating a preview image; and a displaying part for displaying the generated preview image as a preview, wherein the preview image generating part generates a preview image composed of the arrangement of the divided areas and symbols corresponding to the areas.