PROBLEM TO BE SOLVED: To provide an electromagnetic wave transmission metal coating film having high mass production properties and an extremely low transmission attenuation ratio of millimeter waves or electromagnetic waves having frequency smaller than that of millimeter waves: and to provide a radome for a car-mounted radar device using the metal coating film.SOLUTION: The electromagnetic wave transmission metal coating film comprises a metal coating film which is formed on the surface of a base material through a non-electrolytic plating process and is composed of fine metal regions more than 10,000 pieces per a unit area (1 mm) where the fine metal regions adjacent to one another are electrically separated, and which functions for transmitting millimeter waves or electromagnetic waves having frequency smaller than that of the millimeter waves. A radome for a car-mounted radar device using the metal coating film is provided.
