A hinge apparatus for a cover of an image forming apparatus has a hinge body with supporting brackets, movably inserted into a coupling hole positioned in a main body of the image forming apparatus, a hinge cam connected to the cover and pivotably connected to the supporting brackets, and a pressure device disposed at the hinge body to press the hinge cam. Accordingly, the hinge apparatus can be implemented with a simple and easy assembly operation, since it is not a complicated structural connection among the component parts of the hinge apparatus.