An image forming apparatus having a first image obtaining portion which obtains an image of a medium as a first image, a second image obtaining portion which can continuously obtain each image of a plurality of originals as a second image, and an image output section which outputs the image has: an input portion which inputs composition instruction information for instructing composition of first image and each second image; a control portion which makes said first and said second image obtaining portions operative when the composition instruction information is inputted; and an image composing portion which forms each composite image by composing each of the second images sequentially obtained by the second image obtaining portion to the first image obtained by said first image obtaining portion. The image output section outputs the composite images formed by the image composing portion.