A vehicle-use storage battery system comprising: a storage battery; a main circuit that is electrically connected to the storage battery; a circuit breaker that is disposed between the storage battery and the main circuit and is configured to make or break electrical connection between the storage battery and the main circuit; a storage battery management unit that is configured to manage an operating state of the storage battery; a first determiner that is configured to determine whether to break the electrical connection between the storage battery and the main circuit by means of the circuit breaker; a second determiner that is configured to determine, based on at least one of operating states of the storage battery management unit, the first determiner, and the circuit breaker, whether to break the electrical connection between the storage battery and the main circuit by means of the circuit breaker; a main circuit unit including the main circuit and the second determiner; and a storage battery unit including the storage battery, the circuit breaker, the storage battery management unit, and the first determiner, wherein the storage battery unit includes storage battery units, the storage battery units are connected to the main circuit unit, at least one of the first determiner and the second determiner are configured to individually disconnect the storage battery units from the main circuit unit, characterized in that the main circuit unit includes a main-circuit-side communicator, the storage battery unit includes a battery-side communicator that is configured to communicate with the main-circuit-side communicator, and the system being configured to: when the second determiner receives, through the communication between the main-circuit-side communicator and the battery-side communicator, a signal indicating that the first determiner has determined to open the circuit breaker, and detects no opening of the circuit breaker, the second determiner controls the circuit breaker of the storage battery unit to open, the circuit breaker determined to be opened by the first determiner. a storage battery; a main circuit that is electrically connected to the storage battery; a circuit breaker that is disposed between the storage battery and the main circuit and is configured to make or break electrical connection between the storage battery and the main circuit; a storage battery management unit that is configured to manage an operating state of the storage battery; a first determiner that is configured to determine whether to break the electrical connection between the storage battery and the main circuit by means of the circuit breaker; a second determiner that is configured to determine, based on at least one of operating states of the storage battery management unit, the first determiner, and the circuit breaker, whether to break the electrical connection between the storage battery and the main circuit by means of the circuit breaker; a main circuit unit including the main circuit and the second determiner; and a storage battery unit including the storage battery, the circuit breaker, the storage battery management unit, and the first determiner, wherein the storage battery unit includes storage battery units, the storage battery units are connected to the main circuit unit, at least one of the first determiner and the second determiner are configured to individually disconnect the storage battery units from the main circuit unit, characterized in that the main circuit unit includes a main-circuit-side communicator, the storage battery unit includes a battery-side communicator that is configured to communicate with the main-circuit-side communicator, and the system being configured to: when the second determiner receives, through the communication between the main-circuit-side communicator and the battery-side communicator, a signal indicating that the first determiner has determined to open the circuit breaker, and detects no opening of the circuit breaker, the second determiner controls the circuit breaker of the storage battery unit to open, the circuit breaker determined to be opened by the first determiner.