An electrode which can have an improved performance such as higher discharge capacity and in which deterioration due to peeling of an active material layer or the like is difficult to occur are provided. The electrode includes an active material layer including a first protrusion, a second protrusion and a continuous active material film, a metal oxide layer, and a continuous mixed layer. The first protrusion, the second protrusion and the continuous active material film includes silicon. The metal oxide layer includes oxygen and a metal element which is capable of forming silicide by reacting with silicon. The continuous mixed layer includes silicon and the metal element.