A secondary battery includes: a cathode; an anode; and an electrolyte layer containing a nonaqueous electrolytic solution and a polymer compound, wherein the polymer compound contains a block copolymer, and the block copolymer contains vinylidene fluoride, hexafluoro propylene, and one or more of monomethyl maleate, trifluoroethylene, and chlorotrifluoroethylene as polymerization units.