PURPOSE: To decrease the time required for attaining the highest speed of an unmanned vehicle with no load by providing transfer goods detection means for detecting whether transfer goods are loaded on a transfer bed at the time of transfer, and adjustable-speed changing means for changing the speed of a carrier vehicle on the basis of the detection by said detection means.

CONSTITUTION: A carrier controller 2 receiving a carrier command from a host computer 1 transmits travelling information such as travelling speed to an unmanned vehicle side via communications interface 3. The vehicle analyzes said travelling information on the basis of control of main CPU 9 and the change of adjustable speed by an adjustable-speed changing apparatus 11 is conducted according to the detection of transfer goods by a transfer goods detection apparatus 10 of a transfer machine. Then, the change command of said adjustable speed by said adjustable speed changing apparatus 11 is given to a servo CPU 6 to drive a servo amplifier 7.