An image forming apparatus includes a transfer unit, a fixing unit, a first conveyance unit which includes a first conveyance rotator, a first suction fan, and a first suction port, a second conveyance unit which includes a second conveyance rotator, a second suction fan, and a second suction port, and a control unit. The control unit is configured to execute a first mode of changing a rotational speed of the second suction fan from a first rotational speed to a second rotational speed lower than the first rotational speed after a leading edge of the sheet passes through the fixing unit in a case where a sheet having a length longer than a length from the fixing unit to a downstream end of the first suction port in the sheet conveyance direction is conveyed.