Position detection program and a position detection system

A plurality of readers for receiving radio waves from a pre-arranged a defined coordinate RFID (R, R, ...) and, connected to the reader via a local area network, a wireless tag based on the signal from the reader R a position detector for detecting a position and a server (10). Server HDD (13), the position detection program (15) is stored. Position detection program, radio wave from the position detection module for identifying the position of the wireless tag based on the signal from the received radio waves from the detection target radio tag reader (15a), arranged in a predetermined coordinate Makatagu and a sensitivity adjustment module for adjusting (15b) of the receiving sensitivity of each reader on the basis of a signal from the received reader a.