An image forming apparatus includes: a transport path that transports an image forming medium in a top-bottom direction; a first image forming unit including a first intermediate transfer belt, which is disposed so as to face the transport path, to which toner images formed in multiple first toner-image forming units are transferred, and from which the toner images are transferred to the medium transported along the transport path; a second image forming unit including a second intermediate transfer belt, which is disposed upstream of the first image forming unit in a medium transport direction so as to face the transport path, to which toner images formed in multiple second toner-image forming units are transferred, and from which the toner images are transferred to the medium transported along the transport path; and a ventilation path formed between the first image forming unit and the second image forming unit, which are spaced apart.