An image forming apparatus includes a plurality of process cartridges and a pair of frames. Each of the plurality of process cartridges includes a photosensitive drum, a charger and a charger supporting wall. One of the pair of frames has a plurality of first openings such that air outside the pair of frames is sucked between the pair of frames through the first openings. The other of the pair of frames has a plurality of second openings such that air between the pair of frames is discharged outside the pair of frames through the second openings. The first openings are positioned on an opposite side of the charger supporting wall from the photosensitive drum. The second openings are positioned on the same side of the charger supporting wall as the photosensitive drum.