To provide a positioning system capable of positioning the present position of a terminal device, without receiving obstruction of communication waves transmitted by the terminal device.

The positioning device 40 includes a producing means for propagation delay information between terminal mediation devices, for generating propagation delay information 370 between terminal mediation devices indicating time required to propagate terminal information to each agency device 20A, based on transmission time information 366 for terminal information, receipt time information 368 for mediation information, and propagation delay information 356 for mediation information, acquired by an acquisition means for mediation device information; and a producing means for terminal device position information, for creating terminal device position information 372, indicating the position of the terminal device 12, based on mediation device 354 position information and propagation delay information 370 between terminal device devices.