To provide a polymer actuator wherein it is possible to eliminate irregularity on an electrode surface as much as possible (as compared with, for example, talc processing) to achieve stable control and further reduce a sliding resistance between the polymer actuator and a vibration isolation target so that smooth and reliable response can be expected.

The polymer actuator includes a vibration isolating piezoelectric substrate having one flat surface and the other flat surface opposed to each other and an electrode layer formed on each of the one surface and the other surface of the vibration isolating piezoelectric substrate. Each of the electrode layers includes a surface-treated film whose surface is treated with a silicone treatment solution.