An overhead running vehicle 10 uses an absolute position sensor or an encoder to detect its own position. The overhead running vehicle 10 then reports its own position and state to a system controller 14 via a communication line also used as an electrcity feeding line. Further, the overhead running vehicle 10 intercepts reports from other overhead running vehicles 10 to avoid collisions or deadlocks. The system controller 14 and each overhead running vehicle 10 can determine the positions and state of other overhead running vehicles 10. This enables the system to be efficiently operated.