To provide a branch device capable safely and securely running on an X-branch route by a simple structure and enabling the ease of assembling and an improvement in maintainability in a guided traffic system having a mechanical steering device running on a track and formed of running guide rings installed on a vehicle and guide rails installed on a track side.

In this branch device, a liftable auxiliary rail 13 is installed on the track crossing surface X of the X-branch route, the auxiliary rail 13 is fitted to the other end of an arm 14 having one end rotatably pivoted thereon, and a triangular shield plate 26 is installed at a joining part between the arm 14 and the auxiliary rail 13. Rotatable rotating shafts 16 are installed parallel with the auxiliary rail 13. The rotating shaft is connected to the auxiliary rail through a crank 22, The rotating shafts 16 of the auxiliary rail adjacent to each other are connected to each other through a universal joint 24, and the rotating shafts 16 are fixed to each other by a detachable spacer inserted between a bearing device and a step part.