An image forming apparatus which conveys waste toner includes a buffer portion 101 capable of temporarily containing the waste toner and a waste toner container 102 capable of containing the waste toner and a waste toner container 102 capable of containing the waste toner. The waste toner is dominantly contained in the waste toner container 102 compared with the buffer portion 101. When the waste toner container 102 is filled with the waste toner, the waste toner can be contained in the buffer portion 101. An engine controller 120 detects whether the buffer portion 101 is filled with the waste toner 112 or not through a buffer portion waste toner full state detection sensor 105. When the buffer portion 101 is filled with the waste toner 112, the engine controller controls so that a conveyance operation by a first waste toner pipe 103 and an image forming operation are stopped.