A method for continuously subjecting an elongated substrate to vacuum film formation, comprising the steps of: (a) feeding an elongated first substrate wound in a roll form, from a first roll chamber in a first direction from the first roll chamber toward a second roll chamber; (b) degassing the first substrate fed in the first direction; (c) forming a film of a second material on the degassed first substrate, using a target supported by a second cathode electrode of a second film formation chamber; (d) rolling up, in the second roll chamber, the first substrate having the second material film formed thereon, thereby producing the second material film-formed first substrate; (a') feeding an elongated second substrate wound in a roll form, from the second roll chamber in a second direction from the second roll chamber toward the first roll chamber, wherein the second substrate is different from the first substrate; (b') degassing the second substrate fed in the second direction; (c') forming a film of a first material on the degassed second substrate, using a target supported by a first cathode electrode of a first film formation chamber; and (d') rolling up, in the first roll chamber, the second substrate having the first material film formed thereon, thereby producing the first material film-formed second substrate, wherein: in advance of producing the second material film-formed first substrate, the first cathode electrode of the first film formation chamber is removed from the first film formation chamber; and in advance of producing the first material film-formed second substrate, the second cathode electrode of the second film formation chamber is removed from the second film formation chamber. (a) feeding an elongated first substrate wound in a roll form, from a first roll chamber in a first direction from the first roll chamber toward a second roll chamber; (b) degassing the first substrate fed in the first direction; (c) forming a film of a second material on the degassed first substrate, using a target supported by a second cathode electrode of a second film formation chamber; (d) rolling up, in the second roll chamber, the first substrate having the second material film formed thereon, thereby producing the second material film-formed first substrate; (a') feeding an elongated second substrate wound in a roll form, from the second roll chamber in a second direction from the second roll chamber toward the first roll chamber, wherein the second substrate is different from the first substrate; (b') degassing the second substrate fed in the second direction; (c') forming a film of a first material on the degassed second substrate, using a target supported by a first cathode electrode of a first film formation chamber; and (d') rolling up, in the first roll chamber, the second substrate having the first material film formed thereon, thereby producing the first material film-formed second substrate, in advance of producing the second material film-formed first substrate, the first cathode electrode of the first film formation chamber is removed from the first film formation chamber; and in advance of producing the first material film-formed second substrate, the second cathode electrode of the second film formation chamber is removed from the second film formation chamber.