PURPOSE: To hold a straight traveling by detecting a groove orthogonally crossing a traveling direction at the time of a straight traveling by a pair of groove detectors symmetrically arranged on a line orthogonally crossing the traveling direction, detecting a bend by the time deviation of the output, and adjusting the number of rotation of right-and-left driving wheels.

CONSTITUTION: The traveling is started by confirming the groove at a floor face by a groove detector 4C provided at the central part of the lower face of a traveling cart main body, and controlling the traveling direction, and the traveling cart can be prevented from deviating from the traveling direction by allowing it to follow-up the confirmed groove during traveling. Then, symmetrically provided groove detectors 4A and 4B detect the groove orthogonally crossing the traveling direction, and transmit it to a traveling direction correcting circuit 20. At that time, when the output of the groove detector 4A is earlier than the output of the groove detector 4B, the traveling correcting circuit 20 prepares changing amounts corresponding to the output delay of the groove detector 4B, transmits it to a driving motor control circuit 22, increases the number of rotation of a right driving motor 8 according to the changing amounts, and corrects the bend of the traveling direction. Thus, the straight traveling can be operation-controlled.