TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compound: The titanium compound is chosen from alkoxy titanium, titanium bis(ammonium lactate)dihydroxide, titanium bis(lactate) and titanium bis(lactate) titanium(ethyl acetoacetate)diisopropoxide.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The polymer having linear-polyethylene imine structure, is chain-shaped polymer, star-shaped polymer or comb-shaped polymer. The polymer is block copolymer of linear-polyethylene imine block and another polymer block. The ratio of polyethylene imine structure in the polymer is 40 mol% or more. The size of composite nano fiber is 10-1000 nm, preferably 15-200 nm. The composite nano fiber is multi-branch-like nano fiber. Preferred Process: In manufacture of composite material, the amount of alkoxy silane contacted with crystalline polymer filament, is 2-1000 times equivalence with respect to ethyleneimine unit of polymer having polyethylene imine structure. The content of titanium compound in the aqueous solution used for coating composite nano fiber is 1-80 mass%. Preferred Material: The organic-inorganic composite material has multi-branch-like network structure. EXAMPLE - Polyethyl oxazoline (in g) (3) was dissolved in hydrochloric acid aqueous solution (15 ml) and heated at 90degreesC for 10 hours. Acetone (50 ml) was added to the reaction liquid, and polymer was precipitated. The obtained polymer was filtered and washed with methanol, to obtain polyethylene imine powder. The powder was dissolved in distilled water (5 ml). 15% aqueous ammonia (50 ml) was added to the solution, and the resulting solution was left overnight. The obtained polymer was filtered, washed and dried, to obtain linear polyethylene imine (2.2). The obtained linear polyethylene imine was dispersed in water to obtain dispersion liquid. The obtained dispersion liquid was heated and cooled to obtain hydrogel of opaque linear polyethylene imine. The obtained hydrogel was added to liquid mixture of tetramethoxy silane and ethanol. The resulting product was washed with excess acetone, and the obtained solid substance was recovered and dried to form composite of silica and linear polyethylene imine. The obtained composite (3) was added to 50 wt.% aqueous solution of titanium compound (50 ml) and left at room temperature for 40 minutes. The resulting solution was filtered, washed with acetone and dried to obtain white powder (13). The scanning electron microscope of the powder showed that the powder was linear polyethylene imine-silica-titanium oxide composite material having multi-branch-like network structure.