A protection circuit 100 of an energy storage apparatus 20 equipped with external terminals 58A, 58B, the protection circuit 100 being equipped with a reflux circuit 110 connected in parallel to a load 12 connected between the external terminals, and also equipped with a switching circuit 120, wherein: the reflux circuit 110 is equipped with a reflux element 111 which causes an induced current produced when the current to the load 12 is blocked to return to the load 12, and a semiconductor switch 115 which is connected in series to the reflux element 111; and the switching circuit 120 switches the semiconductor switch 115 from conducting to blocking after a delay of a prescribed interval from when a reverse voltage is applied to the external terminals 58A, 58B.