A method of continuously subjecting an elongated substrate to vacuum film formation is disclosed. The method comprises the steps of: feeding a first substrate from a first roll chamber in a first direction from the first roll chamber toward a second roll chamber; degassing the first substrate; forming a film of a second material on the first substrate, in a second film formation chamber; and rolling up the first substrate in the second roll chamber, thereby producing the first substrate, and comprises similar steps to produce a second substrate. In advance of producing the first substrate with the second material film, the first cathode electrode of the first film formation chamber is removed from the first film formation chamber, and, in advance of producing the second substrate with the first material film, the second cathode electrode of the second film formation chamber is removed from the second film formation chamber.