Disclosed are a hinge assembly and a mobile device having the hinge assembly. In the mobile device, a rotation portion 14 slides and rotates on a base portion 10, so as to be inclined to the base portion 10. For this reason, the rotation portion 14 is connected to the base portion by means of the hinge assembly 20 so as to slide and rotate on the base portion 10. The rotation portion 14 slides on the base portion by a predetermined distance, and then rotates to be inclined at a desired angle with respect to the base portion 10. The rotation portion 14 easily rotates with respect to the base portion of the mobile device, so that the status of the mobile device can be easily converted. Further, when the status of the mobile device is converted, the front, rear, left and right of a display screen is not changed. As a result, the mobile device should not have a structure of changing a display direction of the display screen. Further, there is an advantage in that an electric connection between the base portion and the rotation portion by means of a connection link mechanism can be stably achieved.