An electrode includes a core portion including a first metal, and a porous portion disposed in contact with the core portion. The porous portion includes a porous body, a first dielectric layer, and a second dielectric layer. The porous body is integrated with the core portion and includes the first metal. The first dielectric layer covers at least a part of a surface of the porous body. And the second dielectric layer covers at least a part of the first dielectric layer. The first dielectric layer includes oxide of first metal, and the second dielectric layer includes oxide of a second metal. The second metal is different from the first metal. When T is a thickness of the porous portion, the second metal is distributed to a region closer to the core portion than a position of 0.5T from a boundary between the core portion and the porous portion.