The semiconductor memory device of the present invention includes: an interlayer insulating film formed on a semiconductor substrate; a contact plug formed to extend through the interlayer insulating film; and a capacitor formed on the interlayer insulating film so that an electrode of the capacitor is connected with the contact plug. The electrode has an iridium oxide film as an oxygen barrier film. The average grain size of granular crystals constituting the iridium oxide film is a half or less of the thickness of the iridium oxide film.