A position detection apparatus and a medical-device-position detection system that have improved position detection accuracy are provided by setting high amplification for the position detection apparatus. The position detection apparatus includes a circuit that has at least one embedded coil (10a) and that is provided inside an object (10) to be detected a first magnetic-field generating unit (11) for generating a first magnetic field in the region where the embedded coil (10a) is disposed a magnetic-field detecting unit (5, 12) for detecting an induced magnetic field generated at the embedded coil (10a) by the first magnetic field and a second magnetic-field generating unit (23) for generating a second magnetic field having a phase substantially opposite to the phase of the first magnetic field.
