PROBLEM TO BE SOLVED: To provide a sputtering device capable of forming soft magnetic coating free from magnetic anisotropy and small in coercive force at the time of forming thin coating film by a sputtering method and to provide a method for forming soft magnetic coating film using this. SOLUTION: This device is provided with a target 5 arranged on a cathode part 3, a substrate 6 arranged opposite to the target 5 and a coating thickness correcting board 7 arranged between the target 5 and the substrate 6, and the coating thickness correcting board 7 has an opening part 7a having a shape by which the distribution of the coating film thickness is considered. Then, the opening part 7a has plural slits partitioned by walls in the approximately orthogonal direction to the substrate face.