A hinge apparatus for connecting a first housing and a second housing of a portable terminal is provided. The hinge apparatus includes a hinge housing and a damping member. The hinge housing is connected to the second housing and has an internal wall formed with one or more guide grooves extending in a circumferential direction of the hinge housing. The damping member is rotatably received in the hinge housing and rotates as the second housing rotates. The damping member has one or more frictional projections. In a first section corresponding to the position where the second housing is folded onto the first housing, the frictional projections contact the internal wall of the hinge housing. Similarly, in another section corresponding to the position where the rotation of the second housing is stopped after rotating away from the first housing, the frictional projections also contact the internal wall of the hinge housing. As a result, the hinge apparatus dampens impact produced at the moment the housings are folded or stopped after rotating away from each other, thereby improving the endurance and structural stability of the portable terminal.