Provided is a semiconductor device manufacturing method for a capacitor having a dielectric film which can be formed into a thin film, can be formed at a low temperature, and has a readily controllable property. The manufacturing method includes: forming an oxide film or an oxynitride film on a conductor for serving as one electrode of a capacitor; forming, on the oxide film or the oxynitride film, a manganese oxide film for serving as a dielectric film of the capacitor; and forming, on the manganese oxide film, a conductive film for serving as the other electrode of the capacitor.