To provide a noise filter which is capable of closing a capable drawing part, without the need for attaching a ferrite core to an external output cable.

A through-hole that is smaller than the diameter of a cable drawing part 2a is provided at the center of a metallic disc, furthermore, a noise filter 1 which consists of a ferrite cover 1a which has a groove around the through-hole of a flat part of one side, a cylindrical ferrite core 1b which has a through-hole, through which a cable is passed at the center of a cylindrical magnetic material and toroidal ferrite 1c which has an inner diameter that is larger than the outline of the outlet 2a is attached to the drawing part 2a, an external output cable is passed through the through-hole of the core 1c and the gap of the outlet 2a is closed with the core 1c so as to eliminate noise.