To improve conventional position estimation system of radio source, such that since a center station is configured to read out all the arrival direction detection information that received at an internal memory when a predetermined period of time passes after the center station once accumulates it, instances where accumulation time of memory increases more than necessary occurs frequently, resulting in missing of real time behavior.

The center station 12 detects the arrival time of the latest arrival time among all the received arrival direction detection information 13 at an arrival time detecting means 15. A readout timing generating means 16 generates readout timing information setting the time obtained by adding fixed value required to readout to detected arrival time as readout timing time. A readout means 17 starts readout of a memory 14 at a readout time readout timing information indicates to read out all the accumulated arrival direction detection information 13. Thereby, accumulation time of arrival direction detection information of the memory 14 can be minimized to enhance real time behavior of the display of estimated position of radio source.