NOVELTY - The metallic oxide structure has uneven protrusions formed on substrate. The ratio between the diameter of circle obtained by circle conversion of protrusion corresponding to the length of 0.01-10000 microns is 0.1 or more.    USE - The method is used for forming metallic oxide used in ceramic capacitor, actuator, optical wavelength converting element, laser oscillation element, cold cathode element, optical material etc.    ADVANTAGE - By releasing the metallic oxide from metallic compound and spraying unevenly on substrate base material, a metallic oxide structure with specific protrusion can be formed, and used as sensor materials such as optical elements insulator, conductive material, solid electrolyte, fluorescent display tube, electroluminescent (EL) element, cold cathode element, ceramic capacitor, actuator, laser oscillation element, ferroelectric memory, thermistor, varistor, superconductor, electromagnetic shielding agent, an optical dielectric, an optical switch, photosensor, a solar battery, an optical wavelength conversion element, optical absorption filter, thermosensor and gas sensor.    DETAILED DESCRIPTION - A single crystal metallic oxide is formed on substrate by epitaxial growth method. The metal of metallic oxide contains at least one of the metals chosen from one group metals, 2 group metals, group 3 - group 12 metals in periodic table. The metallic compound preferably contains zinc, aluminum, silicon, tin, titanium, zirconium and lead. The ratio between the diameter of circle obtained by circle conversion of protrusion cross-section with a length of 0.01-10000 microns is 0.1 or more and the weighted mean of ratio of diameter of circle obtained by circle conversion of protrusion cross-section is less than 5 or more than 5 alternately. The weighted mean of protrusion length is 1 microns or more. The density of protrusion is 0.01-10000 piece per area corresponding to 10 x 10 microns on metal oxide substance surface.    An INDEPENDENT CLAIM is also included for manufacture of metallic oxide structure which involves sublimating the volatile compound and vaporizing, to release the metallic oxide from metallic compound at gaseous medium at atmosphere pressure. The released metallic oxide is sprayed unevenly on a substrate at the temperature, set higher than that of metallic compound. The substrate has projections with width 0.1 microns or more and is at a height of 0.1 microns or more.    DESCRIPTION OF DRAWING(S) - The figure shows a metallic oxide reactor. (Drawing includes non-English language text).    Flowmeter (1)    Liquid nitrogen trap (2)    Metal compound heating tank (3)    Board (4)    Slit (5)    Nozzle (6)    Heater (8)