A pivot mechanism of the synchronous hinge device is applied to a foldable electronic apparatus. The pivot mechanism can be stably rotated and the distance between two shafts of the dual-shaft hinge is shortened, whereby the electronic device can be smoothly rotated and have a miniaturized and lightweight structure. The pivot mechanism includes a driver disposed on a first shaft and a reactor disposed on a second shaft and a link unit. Spur gears and conical (bevel) gears are respectively disposed at two ends of the link unit and the driver and the reactor. The Spur gears and conical (bevel) gears are engaged with each other to transmit power, whereby the first shaft with the driver and the second shaft with the reactor can be stably synchronously rotated in reverse directions.