A semiconductor device according to an embodiment includes an oxide film containing first element and a conductive film provided to be in contact with the oxide film, containing metal element and oxygen element, and having conductivity. A range of a volume density of the oxygen element in the conductive film is different between cases where the metal element are tungsten (W), molybdenum (Mo), titanium (Ti), chromium (Cr), vanadium (V), iron (Fe), copper (Cu), tantalum (Ta), or niobium (Nb).