An electrical storage system comprising: an electrical storage device in which a plurality of electrical storage blocks are connected in series with each other, each of the plurality of electrical storage blocks including at least one electrical storage element configured to be charged or discharged; a plurality of capacitors each connected in parallel with a corresponding one of the electrical storage blocks and each configured to output a voltage value of the corresponding one of the electrical storage blocks; a relay(SMR-B, SMR-G) configured to switch between an on state where the relay connects the electrical storage device to a load and an off state where the relay(SMR-B, SMR-G) interrupts connection of the electrical storage device with the load; a controller(30, 34) configured to control the relay(SMR-B, SMR-G) so as to cause the relay(SMR-B, SMR-G) to switch between the on or off state; and a current interruption circuit configured to interrupt energization of the electrical storage device by causing the relay(SMR-B, SMR-G) to switch from the on state to the off state, wherein the current interruption circuit includes an alarm circuit configured to output an alarm signal indicating that at least any one of the electrical storage blocks is in an overcharged state by comparing an input voltage value of each electrical storage block input from the capacitors with a threshold, a latch circuit configured to retain the alarm signal and a transistor configured to cause the relay(SMR-B, SMR-G) to switch from the on state to the off state upon reception of an output signal of the latch circuit, the electrical storage system characterized in that the controller(30, 34) is configured to execute control for causing the alarm circuit to output the alarm signal by charging one of the capacitors using an output of a plurality of the electrical storage blocks and then determine an energization state of the electrical storage device, the alarm signal indicating that at least any one of the electrical storage blocks is in an overcharged state, and in that when the electrical storage device is in an energized state after control for outputting the alarm signal is executed, the controller(30, 34) is configured to determine that the current interruption circuit is in an abnormal state. an electrical storage device in which a plurality of electrical storage blocks are connected in series with each other, each of the plurality of electrical storage blocks including at least one electrical storage element configured to be charged or discharged; a plurality of capacitors each connected in parallel with a corresponding one of the electrical storage blocks and each configured to output a voltage value of the corresponding one of the electrical storage blocks; a relay(SMR-B, SMR-G) configured to switch between an on state where the relay connects the electrical storage device to a load and an off state where the relay(SMR-B, SMR-G) interrupts connection of the electrical storage device with the load; a controller(30, 34) configured to control the relay(SMR-B, SMR-G) so as to cause the relay(SMR-B, SMR-G) to switch between the on or off state; and a current interruption circuit configured to interrupt energization of the electrical storage device by causing the relay(SMR-B, SMR-G) to switch from the on state to the off state, wherein the current interruption circuit includes an alarm circuit configured to output an alarm signal indicating that at least any one of the electrical storage blocks is in an overcharged state by comparing an input voltage value of each electrical storage block input from the capacitors with a threshold, a latch circuit configured to retain the alarm signal and a transistor configured to cause the relay(SMR-B, SMR-G) to switch from the on state to the off state upon reception of an output signal of the latch circuit, the electrical storage system characterized in that an alarm circuit configured to output an alarm signal indicating that at least any one of the electrical storage blocks is in an overcharged state by comparing an input voltage value of each electrical storage block input from the capacitors with a threshold, a latch circuit configured to retain the alarm signal and a transistor configured to cause the relay(SMR-B, SMR-G) to switch from the on state to the off state upon reception of an output signal of the latch circuit, the electrical storage system characterized in that the controller(30, 34) is configured to execute control for causing the alarm circuit to output the alarm signal by charging one of the capacitors using an output of a plurality of the electrical storage blocks and then determine an energization state of the electrical storage device, the alarm signal indicating that at least any one of the electrical storage blocks is in an overcharged state, and in that when the electrical storage device is in an energized state after control for outputting the alarm signal is executed, the controller(30, 34) is configured to determine that the current interruption circuit is in an abnormal state.