An upper electrode device applied to the film coating process has a splitter chamber and at least three gas diversion plates; a gas inlet is set on the splitter chamber; the at least three gas diversion plates were fixed on the inside walls of the splitter chamber and used for diverting and outputting the gas introduced into the splitter chamber through the gas inlet. By using the upper electrode device provided by the present disclosure can uniformize the gas used for coating in the film coating process, especially uniformize the gas in the perimeter area and the center area. Consequently, the uniformity of the thickness of the whole film coated is improved.