To provide a race timing system that can time competitors appropriately even if generated electromagnetic fields and reception sensitivities vary.
A loop antenna 20 comprises a substantially rectangular antenna part and a substantially 8-shaped antenna part, and generates an electromagnetic field of a predetermined electromagnetic field strength distribution on each antenna part according to a signal supplied from a signal generation device 10. A radio tag 50, when detecting the electromagnetic field generated by the loop antenna 20 for the first time, measures the electromagnetic field strength for a fixed time to set a threshold. When the second pole change point in the electromagnetic fields on the loop antenna 20 is detected after the threshold setting, the time measured at the timing is specified as a race time. The radio tag 50 sends the specified race time and the like to a receiver 30.
FUKUDA KAZUHIRO
Takanori Mamoru