To provide a position information detection system that enhance the positioning accuracy of a radio mobile terminal.

A position calculation section 33 that calculates a position of a radio mobile terminal in a mobile management station in a position information detection system that detects a current position of the radio mobile terminal refers a detabase 34 that stores the geographical position information of the base stations based on position information making pairs the data of identification codes of the base stations and a reception electric field value sent from the radio mobile terminal through the base station to select proper position information to accurately specify the position of the radio mobile terminal and specifies a current position of the radio mobile terminal from at least one locus in a 1st locus obtained by a calculation formula from the reception electric field value of the selected position information and in a 2nd locus obtained from an equal electric field curve of an electric field generated by the selected base station.