A secondary battery is provided with a positive electrode active material layer a containing a positive electrode active material, a negative electrode active material layer containing a negative electrode active material, an electrolyte layer formed between the positive electrode active material layer and the negative electrode active material layer, and a modification material disposed at an interface between an electrolyte material and at least one electrode active material among the positive electrode active material and the negative electrode active material, and having a higher relative permittivity than the relative permittivity of the electrolyte material.