An image forming apparatus includes: a drawer movable between an inner position and an outer position and supporting a first cartridge including a first photosensitive drum and a first discharge part and a second cartridge including a second photosensitive drum and a second discharge part; and a waste toner box including a first coupling part coupled with the first discharge part and a second coupling part coupled with the second discharge part, in a state where the first cartridge and the second cartridge are supported by the drawer at an inner position and the waste toner box is mounted to the apparatus main body, the waste toner box being movable between a first/second position where the first coupling part and the first discharge part are coupled/decoupled and the second coupling part and the second discharge part are coupled/decoupled.