PURPOSE: To provide a position detecting device by which highly accurate detection becomes possible.

CONSTITUTION: A position detecting device has a magnetic detecting device and a photoelectric detecting device, and in the magnetic detecting device, a magnetic information recording part is arranged on a member interlocking with a moving body, and a detector having yokes 8 and 9 composed of a high magnetic permeability material is arranged so as to be opposed to a minimum information unit recording surface in the recording part, and a coil 15 is wound round the yokes 8 and 9 so as to superimpose alternating current biased magnetic flux upon magnetic flux running toward the yokes 8 and 9 from the recording surface. The tips of the yokes 8 and 9 have the tips shorter than moving dirctional length of the minimum information unit recording surface, and are constituted so as to sense only the magnetic flux on the recording surface opposed to the tips of the yokes 8 and 9. On the other hand, in the photoelectric position detecting device, since positional information created in a positional information recording part is formed in plural signal patterns, detection of an absolute position and detection of a moving distance become possible.