To provide an optical filter capable of effectively removing foreign matter attached to an optical member, and to provide an image forming apparatus using the optical filter.

The optical filter disposed on the surface of the optical member comprises: a base body 62 composed of a pizoelectric material; a comb-line electrode 63 disposed on an edge part of the base body 62; and an electric source of applying a voltage to the electrode 63, wherein the optical filter has such a constitution as to apply the voltage to the electrode 63 and generate a surface elastic wave on the surface of the base body 62.

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