Provided is a position detecting system and a position detecting method capable of stably deriving an accurate position. To this end, an external device (200) of a position detecting system (200) includes drive coils (D) that simultaneously are driven to generate driving magnetic fields drive-signal generators (233) that input drive signals to the drive coils (D), respectively sense coils (S) that detect magnetic fields generated in a detection space (K) a control unit (201) and a drive-coil input-signal adjustment unit (230) that adjust at least one of phases and amplitudes of the drive signals to be input to the drive coils (D) respectively by the drive-signal generators (233) based on the magnetic fields detected by the sense coils (S) and a magnetic field information acquiring unit (210) and a control unit (201) that derive a position of an LC marker (100) based on the magnetic fields detected by the sense coils (S).
