To provide a reactive sputtering device capable of forming a thin film in which target atoms and reactive gas are sufficiently reacted on the surface of a substrate without reducing the film forming rate and to provide a method therefor.

At least either a 2nd introducing port 5 and an exhaust port 6 is located between a target 3 and a substrate 2, and the 2nd introducing port 5 and the exhaust port 6 are arranged in such a manner that a virtual line 9 connecting the center B of the 2nd introducing port 5 and the center A of the exhaust port 6 passes on the substrate 2 or passes through from one side of the substrate 2 to the other side in a state in which the front surface of the substrate 2 is viewed from the target 3.