Abstract: A hinge device for a portable terminal rotatably couples a first housing to a second housing of a portable terminal. The hinge device includes a first hinge cam fixed to one of the housings of the portable terminal and a second hinge cam fixed to the other one of the housings of the portable terminal. The first hinge came has a cam groove on a surface, and the second hinge cam is rotatably received in the cam groove to generate friction with an inner wall of the cam groove. The hinge device has a reduced length and can occupy a smaller area in the portable terminal. Further, the hinge device allows the separate housing to be installed to the portable terminal while maintaining the shape of the portable terminal so that the separate housing slidably moves, thereby allowing increased design flexibility for the portable terminal. Furthermore, since the hinge device requires a small space in the portable terminal, the design specifications of the portable terminal may be easily changed.