To provide a time measuring instrument capable of appropriately measuring race times of individual racers.

A wireless tag 100 receives a mat ID from an electromagnetic field generated on a loop coil 11, detects a pole change point of an electromagnetic field generated on a loop coil 21 and specifies a measured time in the mat ID (time measurement point). The wireless tag 100 generates the mat ID and time information including the mat ID and sends to a receiver 30. The wireless tag 100 stores the specified measured time relatedly to the mat ID in a storage section 107. The measured time measured at each time measurement point is stored relatedly to the mat ID to ensure that the times can be read during polling or after a race ends.