An image forming apparatus includes an endless belt, a plurality of processing units, a cleaning unit, a waste toner retainer, and a waste toner conveying unit. The plurality of processing units is juxtaposed above the endless belt. The cleaning unit is disposed above the endless belt to collect a waste toner deposited on the endless belt. The waste toner retainer is provided in one processing unit in the plurality of processing units. At least one of the other processing units in the plurality of processing units is interposed between the cleaning unit and the one processing unit. The waste toner conveying unit conveys the waste toner collected by the cleaning unit to the waste toner retainer, and extends from the cleaning unit to the waste toner retainer.