PURPOSE: To secure highly accurate position detection and positioning, to provide a stable output for the change of a gap and to reduce cost for construction and maintenance.

CONSTITUTION: On the side surface of a mobile object 3, two cylindrical magnetic sensors 4a and 4b are arranged at a prescribed interval Ls. As a detection panel 1, a magnetic substance having lateral width Lp longer than the interval Ls inside the sensors and shorter than the interval outside the sensors is used and installed at a target stop position on the ground. The detection panel 1 and the magnetic sensors 4a and 4b are installed at correspondent positions and when the mobile object 3 passes through the side part of the detection panel 1, the detection panel 1 and the magnetic sensors 4 are faced to each other leaving a prescribed gap. Positioning control is performed by detecting the position of the mobile object 3 based on the difference of output values from the magnetic sensors 4a and 4b. As a result, the effect caused by the gap can be canceled and the output value decided only by the distance in the moving direction is obtd. and high-accuracy position detection and positioning can be performed.