This paper describes the application of a sputtered perm ally thin film to a common-mode noise filter in the 1 MHz-1 GHz frequency range. The 4-μm-thick perm alloy film exhibits high loss characteristics which are based on the eddy current loss. It is confirmed that a filter whose volume is from a quarter to a half that of a conventional filter (ferrite core) exhibits the same noise attenuation. Moreover, the noise emission from a twisted pair cable is greatly reduced without any increase in the cable volume by employing the permalloy film as a shielding material