To provide a position detection apparatus capable of generating a position detection magnetic field having an appropriate strength according to a physical constitution of a subject.

The position detection apparatus 3 comprises receiving antennas 7a-7d for receiving radio signals, transmission antennas 8a-8d for sending electric supply radio signals to a capsule endoscope 2, a first linear magnetic field generating section 9 for generating a first linear magnetic field, a second linear magnetic field generating section 10 for generating a second linear magnetic field, a diffusing magnetic field generating section 11 for generating a diffusing magnetic field, a treatment apparatus 12 for carrying out a predetermined treatment with regard to the radio signals or the like received via the receiving antennas 7a-7d, and a magnetic field sensor 13 which functions as a physical constitution information detecting means. The magnetic field sensor 13 has the function of detecting magnetic field strength of a position where it is arranged as physical constitution information. The treatment apparatus 12 has the function of controlling the first linear magnetic field generating section 9 or the like on the basis of the magnetic field strength detected by the magnetic field sensor 13.