A secondary battery (100; 800) comprising: a battery case (300; 860); an electrode body (200; 850) that is provided with a positive electrode current collector (221; 811) and a positive electrode active material layer (223; 813) held on the positive electrode current collector, and is housed in the battery case; a terminal (420; 864) disposed to the battery case and connected to the electrode body; a nonaqueous electrolytic solution that is housed in the battery case, and contains a gas generating agent, the gas generating agent generating a gas by reacting at a voltage higher than a predetermined voltage; and a current interrupt device (460; 865) that is configured to interrupt an electrical connection between the electrode body and the terminal when an internal pressure of the battery case becomes higher than a predetermined pressure, the secondary battery characterized in that: the positive electrode active material layer includes a plurality of hollow positive electrode active material particles, a plurality of void supporting particles, and a plurality of conductive material particles; the void supporting particles are configured to provide voids (h) having a pore diameter of 0.5 μm or more in the positive electrode active material layer; the conductive material particles are configured to provide an electrical continuity of the positive electrode active material layer; a ratio of an average particle size of the void supporting particles to an average particle size of the hollow positive electrode active material particles is 1/3 or more and 2 or less; a crushing strength of the void supporting particles is larger than a crushing strength of the conductive material particles; the void supporting particles are solid positive electrode active material particles; a weight ratio of the solid positive electrode active material particles in the positive electrode active material layer is 2% by weight or more and 50% by weight or less; and a weight ratio of the hollow positive electrode active material particles in the positive electrode active material layer is larger than the weight ratio of the solid positive electrode active material particles. a battery case (300; 860); an electrode body (200; 850) that is provided with a positive electrode current collector (221; 811) and a positive electrode active material layer (223; 813) held on the positive electrode current collector, and is housed in the battery case; a terminal (420; 864) disposed to the battery case and connected to the electrode body; a nonaqueous electrolytic solution that is housed in the battery case, and contains a gas generating agent, the gas generating agent generating a gas by reacting at a voltage higher than a predetermined voltage; and a current interrupt device (460; 865) that is configured to interrupt an electrical connection between the electrode body and the terminal when an internal pressure of the battery case becomes higher than a predetermined pressure, the secondary battery characterized in that: the positive electrode active material layer includes a plurality of hollow positive electrode active material particles, a plurality of void supporting particles, and a plurality of conductive material particles; the void supporting particles are configured to provide voids (h) having a pore diameter of 0.5 μm or more in the positive electrode active material layer; the conductive material particles are configured to provide an electrical continuity of the positive electrode active material layer; a ratio of an average particle size of the void supporting particles to an average particle size of the hollow positive electrode active material particles is 1/3 or more and 2 or less; a crushing strength of the void supporting particles is larger than a crushing strength of the conductive material particles; the void supporting particles are solid positive electrode active material particles; a weight ratio of the solid positive electrode active material particles in the positive electrode active material layer is 2% by weight or more and 50% by weight or less; and a weight ratio of the hollow positive electrode active material particles in the positive electrode active material layer is larger than the weight ratio of the solid positive electrode active material particles. the positive electrode active material layer includes a plurality of hollow positive electrode active material particles, a plurality of void supporting particles, and a plurality of conductive material particles; the void supporting particles are configured to provide voids (h) having a pore diameter of 0.5 μm or more in the positive electrode active material layer; the conductive material particles are configured to provide an electrical continuity of the positive electrode active material layer; a ratio of an average particle size of the void supporting particles to an average particle size of the hollow positive electrode active material particles is 1/3 or more and 2 or less; a crushing strength of the void supporting particles is larger than a crushing strength of the conductive material particles; the void supporting particles are solid positive electrode active material particles; a weight ratio of the solid positive electrode active material particles in the positive electrode active material layer is 2% by weight or more and 50% by weight or less; and a weight ratio of the hollow positive electrode active material particles in the positive electrode active material layer is larger than the weight ratio of the solid positive electrode active material particles.