To obtain a new silane-modified polyoxometalate having a potential use as a coating, an electronic part such as a sensor and a magnetic/electric storage device.

This silane-modified polyoxometalate anion is expressed by the formula: YZ(SiRR')n [Z is selected from M11O39-12, M9O34-14 and M17O61-20; M is tungsten or molybdenum; Y is As+5, Si14, B+2, Ge+3, P+5 or Fe+3, when Z is M17O39-12; Y is Si+4, Ge+4 or P+5, when Z is M9O34-14 and Y is AS2+10 or P2+10, when Z is M17O61-20; R is selected from a 1-24C monovalent hydrocarbon group, a halogenated hydrocarbon or a carbon group; R' is selected from hydrogen atom, a monovalent hydrocarbon group, etc.; (n) expresses the number of a groups binding with the polyoxometalate anion (=SiRR')+2, and is 1-3].