A communication system includes plural management control units each managing a state of a battery; and plural terminal devices each acquiring battery information about at least one battery and communicating the acquired battery information with at least one of the plural management control units. At least one of the plural management control units includes an abnormality determination unit that is configured to determine whether an abnormality has occurred in an other management control unit based on communication with the other management control unit via an inter-management communication device for performing communication with the other management control unit.