PURPOSE: To enhance reliability and enable courses to be changed by identifying whether a guide line in present and an oscillating timing is right, and by arranging a control means for controlling a moving means and an oscillating means, and a power source for feeding power to the control means.

CONSTITUTION: A CPU 29 is fixed on a substrate 35 fitted on the base 24b of a carrier 24, and receives signal from a guide line detecting light sensor 25, and it is identified whether a guide line is present and an oscillating timing is right, and motor devices 26, 27 and a parallel crank oscillator 32 are controlled. A power source 30 is fixed on the substrate 35, and power is fed to the CPU 29. When courses are changed, then it is discriminated whether other carriers exist on a course to be moved to or not. Such an information is fed to the CPU 29 from a carrier detecting light sensor and is identified by the CPU 29. When the other carriers are not present, then by the CPU 29, the direction controlling motor device 26 is driven, and the carrier 24 is set in a state close to the right. Accordingly, the carrier 24 can be moved to a second course from a first course.