Abstract: Disclosed is a hinge device for a mobile phone having a rotation type display including a body housing, a folder having a display unit, and a connection member for rotatably connecting the folder to the body housing such that the folder is rotatably moved into an open position or a closed position with respect to the body housing. The hinge device includes a hinge module having a plate shape. The hinge module is accommodated in the folder and rotatably coupled to the connection member while facing the connection member so as to rotate the folder relative to the connection member about a hinge axis thereof.