A tire position determination system including tire pressure detectors respectively attached to tires, axle rotation detectors respectively corresponding to axles, and a receiver located on a vehicle body. Each tire pressure detector detects when reaching a specific position on a rotation trajectory of the corresponding tire and transmits a radio wave including the tire ID. An ID temporary registration unit temporarily registers tire IDs to the memory that are received from the tire pressure detectors existing in a signal receivable area of the receiver. An ID registration acquires axle rotation information from each axle rotation detector whenever receiving the radio wave from each tire pressure detector, and specifies a tire ID of a tire that rotates in synchronism with rotation of each axle to determine the tire position of the tire.