A hinge device is adapted to be installed between two machine bodies that are mounted with a flexible display. The hinge device includes a base member, two rotating modules mounted respectively to opposite sides of the base member and adapted for the machine bodies to be mounted respectively thereto, and a central support plate disposed above the base member and connected between the rotating modules. The central support plate is drivable by the rotating modules to move relative to the base member from a supporting position, where the flexible display is flat and is supported thereby from below, to a receding position, where a display receiving space is provided for receiving a bent portion of the flexible display.