Disclosed is an image forming apparatus in which a visualized background pattern image data in which a latent image is visualized is generated, the generated visualized background pattern image data and an image data of a job are synthesized to generate a visualized background pattern synthesizing image data, and a visualized background pattern synthesizing image in which the latent image is visualized is formed based on the generated visualized background pattern synthesizing image data, to output the visualized background pattern synthesizing image on a printing sheet, at the time of a confirmation printing. Thus, a user can easily confirm the state of an invisible background pattern synthesizing image after reproduction with eyes, before the outputting of the set number of copies to be output.