To surely rewrite the travel distance of the old meter unit to the new meter unit without the travel distance of the new meter being falsely rewritten.

The travel distance display system is equipped with a meter unit 1, a storage step, a read-out step, a comparing step, and a limiting step. The meter unit 1 has a storage part 3 storing the travel distance and a display part 4 displaying the travel distance. In the storage step, a service tester 10 and a database 20b are communicatably connected and the meter specific information stored in the storage part 3 of the old meter unit 1A is read out and stored. The read-out step reads out the meter specific information stored in the storage part 3 of the new meter unit 1B when the new meter unit 1B is mounted. The comparing step compares the meter specific information of the old meter unit 1A stored in the database 20b with the meter specific information of the new meter unit 1B read out by the read-out step. The limiting step limits write-in of the travel distance of the old meter unit 1A in the new meter 1B when the meter specific information does not coincide with each other as the result of the comparing step.