PURPOSE: To simplify ground facility and diversify control content, and to detect and control the position of a transport vehicle accurately by using a guiding means for an operation direction and a light beam as a command information propagation medium.

CONSTITUTION: A laser beam from a laser generator 1y is radiated to a longitudinal path Y1 and reflected by mirrors 11y and 12y is made incident on a photodetector 2y through a longitudinal path Y2. A laser beam is radiated from the laser generator 1x to lateral paths X1WX4 similarly and photodetected by the photodetector 2x. A main controller 30 inputs a signal from the photodetectors 2x and 2y and sends a control signal to the laser generators 1x and 1y to impose modulation on the laser beam. Sub-controllers 31 and 32 are provided at reloading point between the longitudinal paths Y1 and Y2, and lateral paths X3 and X4. Control data from the main controller 30 is supplied to the transport vehicle through the sub-controllers 31 and 32.