A tire position determination system comprising: a plurality of tire air pressure detectors (4a-4d) respectively coupled to a plurality of tires, wherein each tire pressure detector is capable of transmitting a tire air pressure signal, is configured to wait to transmit a radio signal in a first period, and is allowed to transmit a radio signal in a second period; a plurality of axle rotation detection units (22a-22d) respectively arranged on a plurality of axles, wherein each axle rotation detection unit is configured to detect a rotation amount of the corresponding axle and generate axle rotation amount information; and a receiver included in a vehicle body, wherein the receiver is configured to receive a tire air pressure signal from each tire air pressure detector and monitor air pressure of the corresponding tire, characterized in that each tire air pressure detector (4a-4d) includes an information storage that is configured to store a plurality of pieces of timing information, which indicate a timing when the tire air pressure detector is rotated to a certain detector angle, in the first period, during which the tire air pressure detector waits to transmit the radio signal, and a radio transmission control unit that is configured to transmit a plurality of pieces of the timing information, which are stored in the information storage, to the receiver in the second period, during which the radio signal transmission is allowed, and the receiver includes an axle rotation amount reader that is configured to receive axle rotation amount information generated in each axle rotation detection unit, and a position determination unit that is configured to calculate an axle rotation amount corresponding to a point of time when each tire air pressure detector is rotated to the certain detector angle based on timing information, which is received from the radio transmission control unit of the tire air pressure detector, and axle rotation amount information, which is received from the axle rotation amount reader and corresponds to the timing information, to determine a position of the corresponding tire using the calculated axle rotation amount. a plurality of tire air pressure detectors (4a-4d) respectively coupled to a plurality of tires, wherein each tire pressure detector is capable of transmitting a tire air pressure signal, is configured to wait to transmit a radio signal in a first period, and is allowed to transmit a radio signal in a second period; a plurality of axle rotation detection units (22a-22d) respectively arranged on a plurality of axles, wherein each axle rotation detection unit is configured to detect a rotation amount of the corresponding axle and generate axle rotation amount information; and a receiver included in a vehicle body, wherein the receiver is configured to receive a tire air pressure signal from each tire air pressure detector and monitor air pressure of the corresponding tire, characterized in that each tire air pressure detector (4a-4d) includes an information storage that is configured to store a plurality of pieces of timing information, which indicate a timing when the tire air pressure detector is rotated to a certain detector angle, in the first period, during which the tire air pressure detector waits to transmit the radio signal, and a radio transmission control unit that is configured to transmit a plurality of pieces of the timing information, which are stored in the information storage, to the receiver in the second period, during which the radio signal transmission is allowed, and the receiver includes an axle rotation amount reader that is configured to receive axle rotation amount information generated in each axle rotation detection unit, and a position determination unit that is configured to calculate an axle rotation amount corresponding to a point of time when each tire air pressure detector is rotated to the certain detector angle based on timing information, which is received from the radio transmission control unit of the tire air pressure detector, and axle rotation amount information, which is received from the axle rotation amount reader and corresponds to the timing information, to determine a position of the corresponding tire using the calculated axle rotation amount.