An object of this invention is to create an actuator in which the amount of deformation is maintained and no displacement in the reverse direction occurs, even when a constant voltage is continuously applied for a long period of time.As a means for achieving the above object, the invention provides a conductive thin film comprising a polymer gel containing at least one organic molecule selected from the group consisting of electron-donating organic molecules and electron-withdrawing organic molecules, a nano-carbon material, an ionic liquid, and a polymer.