To enable movement to a position corresponding to a halfway point of a guide body by an autonomous travel in a short time.

A travel robot calculates an error quantity about a magnetic tape on the basis of the ON state of a magnetism sensor (S6) at the time of a guide travel (S4: YES) and calculates a controlled variable from the error quantity (S7) to travel on a magnetic tape. Here, when the robot moves to a halfway point of the specific magnetic tape, an autonomous travel is made (S4: NO) and a sensor output monitor process is performed to monitor whether or not the magnetism sensor turns ON (S10). To end the autonomous travel in this case (S4: YES), a virtual path having a specific distance in a specific direction is set for a magnetic tape according to the ON state of the magnetism sensor (S11) unless it is positioned on the magnetic tape, and control is so performed that its virtual error becomes zero (S12).