A transformer is provided to prevent deterioration of a loss characteristic of materials with respect to the electric translator using an amorphous thin strip as an iron core. An transformer includes an iron core formed by an amorphous thin strip(1) in a ring shape and an exciting coil. An insulating thin film(2) is formed on at least one surface of the amorphous thin strip. The insulating thin film is formed in a process of manufacturing the amorphous thin strip to the transformer iron core. The insulating thin film is formed on a surface of the iron core material by a thickness of about 1um. The insulating thin film is formed by deposition of silane material.
