Abstract: The present invention relates to a hinge appartus using an engagement structure between a rotating cam, and solves problems of a conventional hinge apparatus that the assembility has been deteriorated and the manufacture costs have been increased, by reducing the number of parts and improving their structures compared with the conventional hinge apparatus. Such a hinge apparatus has an advantage in that the number of parts can be reduced by allowing the rotation cam to be secured to the shaft by forming the engagement protrusions at the one longitudinal end of the shaft and forming the engagement passages and the engagement grooves in the rotating cam. Furthermore, the hinge apparatus according to the present invention has further advantages in that since the number of parts is reduced, the number of assembly processes can be reduced, and the unit cost and then the manufacture costs can be lowered.