The present invention provides an electroactive solid-state actuator, including a solid polymer electrolyte film having first and second main surfaces facing each other, and first and second conductive polymer layers infiltrated into the first and second main surfaces of the solid polymer electrolyte film. Further, a method of manufacturing the electroactive solid-state actuator is provided, the method including preparing a solid polymer film having first and second main surfaces facing each other, infiltrating a monomer of a conductive polymer into the first and second main surfaces of the solid polymer film, followed by polymerization, to form first and second conductive polymer layers, and immersing the solid polymer film into an ionic liquid or liquid electrolyte to be converted to an electrically conductive polymer.