A capsule medical system is provided that accurately detects the location at which biological information, such as an image captured in a living body, is acquired. A circular loop antenna 23 incorporated in an endoscopic capsule traveling in a living body transmits a high-frequency signal and a plurality of antennas 11 a to 11i disposed on a body surface of the living body receives the signal. A CPU 36 defines the initial location and orientation of the antenna 23. The CPU then performs an estimation process on the initial location and orientation so as to compute new estimated location and orientation and update the initial location and orientation to the new location and orientation. The CPU similarly performs the estimation process on the updated location and orientation. The CPU performs accurate location estimation by repeatedly performing the estimation process until the amount of shift of the location computed and updated by the estimation process reaches a sufficiently small value.
