To provide a game system, a game device, and a local managing device that can be operated flexibly while ensuring security by performing communication with a managing device.

A CU performs limited operation of a board initial key mode (limited communication mode) even if no board authentication keys are received from a key management server, and switches from the board initial key mode (limited communication mode) to a board authentication key mode (normal communication mode) if a game machine is not operating when receiving a board authentication key from the key management server.