The present invention provides an actuator which can obtain a large displacement in a moving part, and suppresses the deterioration due to a counteracting force of the moving part in a stationary part. The actuator has a pair of electrode layers which contain a conductive material and a polymer, and an ionic conduction layer which is sandwiched between the pair of the electrode layers, wherein the content of the conductive material contained in the electrode layer is larger in the stationary part of the actuator than in the moving part of the actuator. The content of the conductive material contained in the electrode layer increases toward the stationary part of the actuator from the moving part.