To provide a variable optical attenuator having practical independence of a wavelength and polarization.

This attenuator internally has a thin element 40 having plural opening parts therein. This element 40 is used as a component for an optical filter. The plural opening parts are located so as to increase the size of most of opening parts along the distance of the thin element 40. The plural opening parts are made into pattern array designed to change the rate of transmitted light from one end of a pattern to the other end. One end side of the element 40 forms a low attenuation end part 30 and the other end side forms a high attenuation end part 20. The attenuation rate of optical transmission is varied by moving the element 40 in the direction of the longitudinal axis with respect to a light beam transmitted through the element 40.