A position detection system comprising: a mobile station having a mobile station reference clock circuit, a radio signal transmission circuit, and a transmission antenna; a reference station having a reference station reference clock circuit, a radio signal transmission circuit, and a transmission antenna; and at least three or more fixed stations (4, 5, 6) each having a fixed station reference clock circuit (4A, 5A, 6A), a radio signal reception circuit (4C, 5C, 6C), and a reception antenna (4D, 5D, 6D), wherein the fixed station reference clock circuits (4A, 5A, 6A) of the three or more fixed stations (4, 5, 6) each asynchronously and independently operate and generate reference clocks with the same frequency as one another, the mobile station intermittently transmits a first radio signal based on a reference clock of the mobile station reference clock circuit, the reference station is disposed at a predetermined position and intermittently transmits a second radio signal based on a reference clock of the reference station reference clock circuit, each of the fixed stations (4, 5, 6) receives the first radio signal and extracts a phase difference between a carrier included in the first radio signal and each of the reference clocks of each of the fixed stations (4, 5, 6), receives the second radio signal and extracts a phase difference between a carrier included in the second radio signal and each of the reference clocks of each of the fixed stations (4, 5, 6), a phase offset of the reference clock of each of the fixed stations (4, 5, 6) is canceled using phase difference information between the mobile station and each of the fixed stations (4, 5, 6) and phase difference information between the reference station and each of the fixed stations (4, 5, 6), distance information between each of the fixed stations (4, 5, 6) and the mobile station is obtained, and a position of the mobile station is calculated. a mobile station having a mobile station reference clock circuit, a radio signal transmission circuit, and a transmission antenna; a reference station having a reference station reference clock circuit, a radio signal transmission circuit, and a transmission antenna; and at least three or more fixed stations (4, 5, 6) each having a fixed station reference clock circuit (4A, 5A, 6A), a radio signal reception circuit (4C, 5C, 6C), and a reception antenna (4D, 5D, 6D), wherein the fixed station reference clock circuits (4A, 5A, 6A) of the three or more fixed stations (4, 5, 6) each asynchronously and independently operate and generate reference clocks with the same frequency as one another, the mobile station intermittently transmits a first radio signal based on a reference clock of the mobile station reference clock circuit, the reference station is disposed at a predetermined position and intermittently transmits a second radio signal based on a reference clock of the reference station reference clock circuit, each of the fixed stations (4, 5, 6) receives the first radio signal and extracts a phase difference between a carrier included in the first radio signal and each of the reference clocks of each of the fixed stations (4, 5, 6), receives the second radio signal and extracts a phase difference between a carrier included in the second radio signal and each of the reference clocks of each of the fixed stations (4, 5, 6), a phase offset of the reference clock of each of the fixed stations (4, 5, 6) is canceled using phase difference information between the mobile station and each of the fixed stations (4, 5, 6) and phase difference information between the reference station and each of the fixed stations (4, 5, 6), distance information between each of the fixed stations (4, 5, 6) and the mobile station is obtained, and a position of the mobile station is calculated.