vehicle determination sensors 7 a and 7 b of fig4 and logic such as an or condition are used there is the effect that the trailing vehicle is effectively moved forward note that as specific embodiments of the above described long range detection sensor and the short range detection sensor there are conical beam sensors which output long conical beams beam scanning sensors which scans beams and the like 0095 fig5 is a view showing one example of using conical beam sensors as sensors s 1 and s 2 of fig1 to detect the upper end and lower end fig5 a is a view showing the detection range when the vehicle is seen from the side surface and fig5 b is a view showing the detection range when the vehicle is shown upper side thus when the conical beam sensors are used as sensors s 1 and s 2 the detecting range has a conical shape expanding widely in a width direction and thinly in a height direction moreover fig7 shows one example of a detection range in this figure the conical beam sensors shown in fig5 are arranged near the outer periphery of the vehicle 41 also fig6 a and fig6 b are views each showing examples of the detection range of the conical beam sensor as illustrated in these figures it is preferably that the sensor has a wide detection range in which obstructions near the vehicle are detected 0099 fig8 is a schematic view showing one example of the beam scan sensor this figure shows a state in which scanning with rays of light emitted from an led 42 which is provided at the front surface of an agv 41 that runs on the floor surface.