It is possible to dispose a magnetic-field detecting unit in proximity to a detected object, so that the position of the detected object is detected precisely, while reducing the size and cost of the device. Provided is a position detecting device (1) comprising a first magnetic-field generating unit (2) that includes at least one magnetic-field generating coil and that generates a first magnetic field in a detection space (S) where a detected object (3) provided with a circuit including at least one built-in coil (3a) is disposed a magnetic-field detecting unit (4) having a plurality of detecting coils (4a) arrayed to detect an induced magnetic field generated from the built-in coil (3a) by the generated first magnetic field and a second magnetic-field generating unit (6) that includes at least one magnetic-field generating coil, that generates a second magnetic field, and that includes a magnetic-field component having a phase substantially opposite to the first magnetic field generated by the first magnetic-field generating unit (2) and entering the detecting coils (4a), wherein the first magnetic-field generating unit (2) and the detecting coils (4a) are disposed so that a generating direction of the first magnetic field and a detecting direction of the induced magnetic field intersect each other.
