To provide a game medium lending system which is improved in security protection of an ID in a fare adjustment card by preventing an unfair act by a copy card etc.

Balance information is related to an ID preliminarily recorded in an identification medium thrown from outside into a token lending machine and stored in an island controller. When a player moves to another game machine and plays another game, the player inserts the identification medium into a token lending machine equipped neighboring the game machine to get balance information related to the ID in the identification medium and adjusts the balance using a fare adjustment card. A fare adjustment card after completing the adjustment is reused by updating the ID to another ID by a registering function and an updating function of a fare adjustment machine.