Developing unit and image forming apparatus having the same

A developing unit includes a waste toner housing (100) having an upper housing (110) and a lower housing (120) which face each other, at least one support unit (200) to allow connection between the upper and lower housings, and to support facing surfaces of the upper and lower housings, and a toner housing which is disposed on a lower part of the waste toner housing and is spaced apart from the waste toner housing at a predetermined distance. Accordingly, the waste toner housing is prevented from being deformed by heat and pressure, and thus white lines on images, flowback of waste toner and insufficient cleaning, which are caused by interference with the light path due to deformation of the waste toner housing, can be reduced. Additionally, tolerance can be greatly reduced as a result of resolving the problem of deformation of the waste toner housing, so a developing unit having a smaller size can be provided.