PURPOSE: To perform an easy and precise position detection by providing first and second marker detectors, a direction signal generating means, a count signal generating means and an UP/DOWN counter.

CONSTITUTION: A direction signal is generated by a direction signal generating means 3 on the basis of the detection results of a first marker detector 1 and a second marker detector 2, the output signal of the detector 1 or detector 2 is made into an UP signal or DOWN signal according to the respective direction signals by a count signal generating means 5, and the increment/decrement of each UP signal/DOWN signal is performed by an UP/DOWN counter 5 to detect the position according to the moving direction and moving quantity of a moving body. The respective direction signals cause delays of the same degree to the moving quantity of the moving body regardless of the moving direction, and increment/decrement is performed so that the delays of the respective direction signals are mutually canceled every reversion of the moving direction of the moving body. Therefore, the precise position of the moving body can be detected with a simple structure.