An image forming apparatus that performs booklet printing is provided which includes an information acquisition device, an image data acquisition device, a storage device, and an execution device. The information acquisition device acquires a total number of pages of image data to be printed. The image data acquisition device sequentially acquires the image data by page unit. The storage device stores the image data acquired by the image data acquisition device. The execution device sequentially executes printing of the image data for four pages to be printed on one and same sheet as collected, when the image data for (2N+2) pages or above are stored in the storage device, where N is a positive integer corresponding to a number of sheets necessary for booklet printing of the total number of pages acquired by the information acquisition device.