TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The composite material further contains lanthanum, neodymium, praseodymium, samarium, yttrium, calcium, titanium, iron, zirconium and/or aluminum as addition metal. The composite material further contains metal ultrafine particles supported on the surface of metal oxide microparticles. Preferred Metal: The metal of metal particle has ionization tendency less than ionization tendency of zinc, and is silver, platinum, rhodium, palladium, ruthenium, iridium, osmium, gold and/or copper. The metal particle is oxygen free material particle consisting of an oxygen free material which separates oxygen from oxygen-containing substance and produces active oxygen. The oxygen free material contains silver. The metal oxide of metal oxide microparticles is oxide of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium, zirconium, iron, titanium, aluminum, magnesium, cobalt, nickel, manganese, chromium, molybdenum and/or vanadium, complex oxide or solid solution. The oxygen active-type movement material particle consisting of oxygen active-type movement material and metal oxide microparticles which are capable of moving active oxygen produced by oxygen free material. The oxygen active-type movement material is a complex oxide containing cerium oxide. The metal ultrafine particles have ionization tendency less than ionization tendency of hydrogen, and contains same metal as metal of metal particles. Preferred Properties: The average primary particle size of metal particles and metal oxide microparticles after baking at 500degreesC in air for 5 hours is 1-75 nm and 10-100 nm, respectively. The average primary particle size of metal particles and metal oxide microparticles after baking at 800degreesC in air for 5 hours is 8-100 nm and 10-400 nm, respectively. The metal oxide microparticle contains nitrogen (90 vol.%) and oxygen (10 vol.%). The average particle size of metal particles is 1.3 times or more of the average primary particle size of metal oxide microparticles. The average particle diameter of aggregate is 0.05-0.5 microns. The aggregate contains 60 vol.% or more of particles having particle size within the range of plus minus 50% of average particle diameter. The base material has core of 1-300 microns, and the coat layer has average thickness of 0.5-50 times the average particle diameter of aggregate. Preferred Method: The metallic compound microparticle is produced in the presence of pH adjuster. The aggregate precursor is obtained by reducing metallic compound microparticle with metal particle precipitates. The metallic compound is produced from metallic salt in the presence of a complex agent. EXAMPLE - Cerium nitrate (Ce(NO3)3.6H2O) (in g) (50.49) and silver nitrate (29.63) were dissolved in water (120 ml). Then, aqueous ammonia (35.6) was added and stirred for 10 minutes. The reaction solution was heated at 120degreesC in presence of water, and flocculation process was carried out for 2 hours. The obtained deposit (aggregate precursor) was baked at 500degreesC in air for 5 hours, and silver-cerium oxide composite material was obtained.