It is an object of the present invention to stably perform a position detecting process of a detected object having an LC marker contained therein. A position detecting device (10) according to the present invention includes plural sets of drive coils (DX, DY, DZ), a magnetic-field-generating-coil switching unit (15) that switches drive coils that apply a magnetic field to an LC marker (2a) in a capsule endoscope (2) among the sets of the drive coils (DX, DY, DZ), a storage unit (19) that stores predetermined information of a selecting condition of the drive coils, and a control unit (20), thereby detecting a position of the capsule endoscope (2) based on a detection result of an induced magnetic field from the LC marker (2a). The control unit (20) determines a selecting condition of the drive coils based on the predetermined information, and selects drive coils that satisfy the determined selecting condition from the sets of the drive coils (DX, DY, DZ), thereby controlling the magnetic-field-generating-coil switching unit (15) to switch to the selected drive coils.
