A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a positive electrode active material layer including a lithium-cobalt composite oxide. The lithium-cobalt composite oxide has a layered rock-salt crystal structure. The negative electrode includes a negative electrode active material layer including graphite. When the secondary battery is charged and discharged with an upper limit of a closed circuit voltage being set to 4.42 V or higher, a unit capacity (mAh/g) satisfies a condition represented by 168 mAh/g≤unit capacity (mAh/g)≤(−0.28×area rate (%)+178) mAh/g.