A tire position registration system comprising: tire valves (4: 4a-4d) respectively arranged on tires (2: 2a-2d) and capable of transmitting tire pressure data, wherein each of the tire valves (4: 4a-4d) is capable of transmitting a radio wave including a unique valve ID when reaching a specified position on a rotation path of the corresponding tire; axle rotation detectors (22: 22a-22d) arranged in correspondence with axles (18: 18a-18d), wherein each of the axle rotation detectors (22: 22a-22d) is configured to output axle rotation information (Dc) that indicates a rotation position of the corresponding axle; and a receiver configured to receive the radio wave transmitted from each of the tire valves (4: 4a-4d) and register the valve ID in association with a tire position, characterized in that the receiver includes a position determination function unit configured to determine the tire positions of the tires (2: 2a-2d) corresponding to the valve IDs by obtaining the axle rotation information (Dc) for each of the axles (18: 18a-18d) whenever receiving the radio wave from each of the tire valves (4: 4a-4d) and checking which one of the axles (18: 18a-18d) and the tire identified by the valve ID are synchronously rotating based on the axle rotation information (Dc) of each of the axles (18: 18a-18d), and the position determination function unit includes a tolerance region setting unit configured to estimate a parent population of the axle rotation information (Dc) of each of the axles (18: 18a-18d) for each valve ID from a data group of the axle rotation information (Dc) of each of the axles (18: 18a-18d) obtained for each valve ID and set a synchronized wheel tolerance region for each parent population based on a population mean (μ), which is a mean of the parent population, wherein the synchronized wheel tolerance region functions as an index for determining validity of the corresponding axle rotation information (Dc), and a position specification unit configured to specify the tire position by determining whether or not the axle rotation information (Dc) obtained for each valve ID is included in the synchronized wheel tolerance region of the corresponding parent population and specifying the axle rotating in synchronization with the tire corresponding to the valve ID. tire valves (4: 4a-4d) respectively arranged on tires (2: 2a-2d) and capable of transmitting tire pressure data, wherein each of the tire valves (4: 4a-4d) is capable of transmitting a radio wave including a unique valve ID when reaching a specified position on a rotation path of the corresponding tire; axle rotation detectors (22: 22a-22d) arranged in correspondence with axles (18: 18a-18d), wherein each of the axle rotation detectors (22: 22a-22d) is configured to output axle rotation information (Dc) that indicates a rotation position of the corresponding axle; and a receiver configured to receive the radio wave transmitted from each of the tire valves (4: 4a-4d) and register the valve ID in association with a tire position, characterized in that the receiver includes a position determination function unit configured to determine the tire positions of the tires (2: 2a-2d) corresponding to the valve IDs by obtaining the axle rotation information (Dc) for each of the axles (18: 18a-18d) whenever receiving the radio wave from each of the tire valves (4: 4a-4d) and checking which one of the axles (18: 18a-18d) and the tire identified by the valve ID are synchronously rotating based on the axle rotation information (Dc) of each of the axles (18: 18a-18d), and the position determination function unit includes a tolerance region setting unit configured to estimate a parent population of the axle rotation information (Dc) of each of the axles (18: 18a-18d) for each valve ID from a data group of the axle rotation information (Dc) of each of the axles (18: 18a-18d) obtained for each valve ID and set a synchronized wheel tolerance region for each parent population based on a population mean (μ), which is a mean of the parent population, wherein the synchronized wheel tolerance region functions as an index for determining validity of the corresponding axle rotation information (Dc), and a position specification unit configured to specify the tire position by determining whether or not the axle rotation information (Dc) obtained for each valve ID is included in the synchronized wheel tolerance region of the corresponding parent population and specifying the axle rotating in synchronization with the tire corresponding to the valve ID. a tolerance region setting unit configured to estimate a parent population of the axle rotation information (Dc) of each of the axles (18: 18a-18d) for each valve ID from a data group of the axle rotation information (Dc) of each of the axles (18: 18a-18d) obtained for each valve ID and set a synchronized wheel tolerance region for each parent population based on a population mean (μ), which is a mean of the parent population, wherein the synchronized wheel tolerance region functions as an index for determining validity of the corresponding axle rotation information (Dc), and a position specification unit configured to specify the tire position by determining whether or not the axle rotation information (Dc) obtained for each valve ID is included in the synchronized wheel tolerance region of the corresponding parent population and specifying the axle rotating in synchronization with the tire corresponding to the valve ID.