Abstract: An image forming system which makes clear the point in time at which initial information transmission for all peripheral devices connected to an image forming apparatus serving as the main device is complete, even when the peripheral devices are attached in various combinations, to thereby reduce the time until it is possible for a user to start operation to the lowest level possible, and to reduce waiting time for powering on. The image forming system such as a copying machine includes at least one peripheral device which can be serially connected to a main body of the copying machine, and communication means for performing communication with the most upstream peripheral device of the peripheral devices. When turned on or reset, the image forming system displays functions of the peripheral devices on an operating unit based on initial information delivered from the peripheral devices.