A sputtering device, comprising: a sputtering cathode, comprising: a sputtering target having a rectangular tubular shape, i.e. the cross-sectional shape thereof is a rectangle, having a pair of long side sections facing each other, an erosion surface facing inward; and a magnet circuit, comprising: a pair of permanent magnets disposed near an outer surface of each of the long side sections, wherein each of the permanent magnets is disposed toward an open upper or lower end of the sputtering target and has a north pole and a south pole, wherein the north pole of a first permanent magnet of the pair of permanent magnets faces toward the sputtering target and the south pole of the first permanent magnet faces away from the sputtering target, and the south pole of a second permanent magnet of the pair of permanent magnets faces toward the sputtering target and the north pole of the second permanent magnet faces away from the sputtering target; and the magnet circuit forms an arrangement such that each north pole of each first permanent magnet is disposed toward the open upper end of the sputtering target, and each south pole of each second permanent magnet is disposed toward the open lower end of the sputtering target, and a yoke extending between and connecting the south pole of the first permanent magnet and the north pole of the second permanent magnet; and the magnet circuit provides on each of the long side sections a magnetic field constituted by lines of magnetic force extending between the north pole of the first permanent magnet and the south pole of the second permanent magnet, such that the plasma is confined to regions within the rectangular interior region of the sputtering target that are adjacent to the sputtering erosion surface; and an anode disposed such that the erosion surface of the sputtering target is exposed; and wherein while moving a body to be film-formed having a film formation region having a narrower width than the long side sections of the sputtering target in a direction traversing the long side sections of the sputtering target for the sputtering target at a constant speed above a space surrounded by the sputtering target, discharge is performed such that a plasma circulating along the inner surface of the sputtering target is generated, and the inner surface of the long side sections of the sputtering target is sputtered by ions in the plasma generated by a sputtering gas to perform film formation in the film formation region of the body to be film-formed. a sputtering target having a rectangular tubular shape, i.e. the cross-sectional shape thereof is a rectangle, having a pair of long side sections facing each other, an erosion surface facing inward; and a magnet circuit, comprising: a pair of permanent magnets disposed near an outer surface of each of the long side sections, wherein each of the permanent magnets is disposed toward an open upper or lower end of the sputtering target and has a north pole and a south pole, wherein the north pole of a first permanent magnet of the pair of permanent magnets faces toward the sputtering target and the south pole of the first permanent magnet faces away from the sputtering target, and the south pole of a second permanent magnet of the pair of permanent magnets faces toward the sputtering target and the north pole of the second permanent magnet faces away from the sputtering target; and the north pole of a first permanent magnet of the pair of permanent magnets faces toward the sputtering target and the south pole of the first permanent magnet faces away from the sputtering target, and the south pole of a second permanent magnet of the pair of permanent magnets faces toward the sputtering target and the north pole of the second permanent magnet faces away from the sputtering target; and the magnet circuit forms an arrangement such that each north pole of each first permanent magnet is disposed toward the open upper end of the sputtering target, and each south pole of each second permanent magnet is disposed toward the open lower end of the sputtering target, and a yoke extending between and connecting the south pole of the first permanent magnet and the north pole of the second permanent magnet; and the magnet circuit provides on each of the long side sections a magnetic field constituted by lines of magnetic force extending between the north pole of the first permanent magnet and the south pole of the second permanent magnet, such that the plasma is confined to regions within the rectangular interior region of the sputtering target that are adjacent to the sputtering erosion surface; and an anode disposed such that the erosion surface of the sputtering target is exposed; and wherein while moving a body to be film-formed having a film formation region having a narrower width than the long side sections of the sputtering target in a direction traversing the long side sections of the sputtering target for the sputtering target at a constant speed above a space surrounded by the sputtering target, discharge is performed such that a plasma circulating along the inner surface of the sputtering target is generated, and the inner surface of the long side sections of the sputtering target is sputtered by ions in the plasma generated by a sputtering gas to perform film formation in the film formation region of the body to be film-formed.