A sealed nonaqueous secondary battery comprising a sealed-end battery case containing an electrodes assembly composed of a cathode, and an anode both capable of intercalating and deintercalating a light metal, a separator therebetween and a nonaqueous electrolytic solution, the opening of said battery case being sealed with an insulating gasket which is provided at the inner periphery of said opening and a sealing part which is held by the gasket and serves as a cathode or anode terminal, wherein the sealing part comprises an explosion-proof valve which is capable of being deformed to the direction opposite to the electrodes assembly with an increase in internal pressure, a vented terminal cap which is provided above the explosion-proof valve in the side opposite to the electrodes assembly, and a current breaker which is provided between the explosion-proof valve and the terminal cap; the current breaker having a piled structure composed of a first electric conductor having a penetrated hole which is provided at a side of the explosion-proof valve, an intermediate insulator having a penetrated hole at the central portion thereof, and a second electric conductor having a penetrated hole which is provided at a side of the terminal cap; the first electric conductor and the second electric conductor being electrically connected at the center thereof; and the first electric conductor having a thin part at the periphery of its joint with the second electric conductor.