An object is to improve safety. Provided is a power storage system including a battery apparatus 1; a power converter 2 provided between the battery apparatus 1 and a load 3 and that can control power supplied from the battery apparatus 1 to the load 3; and a battery monitoring circuit 4 that detects an abnormality in the battery apparatus 1. When an abnormality in the battery apparatus 1 is detected by the battery monitoring circuit 4, the power converter 2 supplies power stored in the battery apparatus 1 to the load 3 or to an internally provided internal load at or below a current value or power value that is set in advance, or alternatively, at a current value or power value that the load 3 demands, within a range that does not exceed an upper limit that is set in advance.