A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a positive electrode active material layer. The positive electrode active material layer includes N-methyl-2-pyrrolidone. Where the positive electrode active material layer is divided equally in a width direction into two end regions and two middle regions located between the two end regions, a ratio of a content of N-methyl-2-pyrrolidone in the two middle regions to a content of N-methyl-2-pyrrolidone in the two end regions is greater than or equal to 4 and less than or equal to 8.