An image forming apparatus allowing a user to easily access an operating section even in a large-size apparatus can be provided. An image forming apparatus 100 includes a main machine 110 including an operating section 113 and capable of functioning as a multifunction machine by itself, and at least one option machine 120 to 190 added to a side-face side of an enclosure 111 of the main machine. The apparatus 100 includes the operating section 113 at a fixed position in the width direction of the enclosure. The enclosure has a unified first color of a same tone at a front face thereof, and an operating position line 101 is formed at a part of the front face of the enclosure and has a second color that is clearly different from the first color so as to be a guide indicating a position of the operating section 113.