Abstract: The present invention relates to a cathode composed of a perovskite-type or fluorite-type mixed metal oxide containing molybdenum, to a composite comprising the mixed metal oxide and to a solid oxide fuel cell comprising the cathode. The cathode mixed metal oxide has an empirical formula unit: EaTbMocOn wherein: T is one or more transition metal elements other than Mo; E is one or more metal elements selected from the group consisting of lanthanide metal elements, alkali metal elements, alkaline earth metal elements, Pb and Bi; and a, b, c, and n are non-zero numerals which may be the same or different for each element.