Position detecting device, medical device guiding system, position detecting method, and medical device guiding method

A position detecting device comprising:

• a first magnetic-field generating unit that includes at least one magnetic-field generating coil and that generates a first magnetic field in a detection space where a detected object provided with a circuit including at least one built-in coil is disposed;
• a magnetic-field detecting unit having a plurality of detecting coils arrayed to detect an induced magnetic field generated from the built-in coil by the first magnetic field generated by the first magnetic-field generating unit;
• and
• a second magnetic-field generating unit that includes at least one magnetic-field generating coil and that generates a second magnetic field, which includes a magnetic-field component having a phase substantially opposite to the first magnetic field generated by the first magnetic-field generating unit and entering the detecting coils,
• wherein the first magnetic-field generating unit and the detecting coils are disposed so that a generating direction of the first magnetic field and a detecting direction of the induced magnetic field intersect each other.