A method and apparatus for processing a thin film able to easily form grooves in a conductive thin film on an insulating substrate, comprising bringing a first electrode into contact with the conductive thin film, maintaining a conductive state between a tip of a second electrode with a voltage applied with respect to the first electrode and the surface of the conductive thin film, and using the tip of the second electrode to scan the conductive thin film so as to thereby form grooves passing through the thickness of the conductive thin film and exposing the surface of the insulating substrate at their bottoms in the conductive thin film.