NOVELTY - A triazine-ring-containing hyperbranched polymer is new.    USE - New triazine-ring-containing hyperbranched polymer is used in compositions used for forming films in electronic device, optical components, and solid-state image sensors (all claimed), and as high-heat-resistance insulating material and component for lenses which require high refractive index. The electronic device includes LCDs, organic electroluminescent displays, optical semiconductor (LED) elements, organic thin-film solar cells, dye-sensitized solar cells, and organic thin-film transistors (TFT). The film is used as planarizing film and conformal film on flush-mounting film on photodiode of solid-state image sensors, color filters, micro lenses, and micro lenses.    ADVANTAGE - The new polymer has excellent heat resistance, transparency, handleability, and solubility with respect to organic solvents, high refractive index, and low volumetric shrinkage, and is obtained without using a metal oxide and without gelatinization. The composition obtained using the polymer provides films of uniform thickness, and the process margin during device production is expanded. The polymer can be colored easily.    DETAILED DESCRIPTION - A new triazine-ring-containing hyperbranched polymer consists of a repeating unit of formula (I or II).    R,R'=H, alkyl, alkoxy, aryl or aralkyl;    R"=alkyl, aralkyl, aryl, alkylamino, alkoxysilyl containing alkylamino group, aralkylamino, arylamino, alkoxy, aralkyloxy, or aryloxy;    Ar=group chosen from 17 groups e.g. groups of formula (i)-(v);    R1-R4,R24-R31,R69-R76,R89-R96,R113-R120=H, halo, carboxy, sulfone, 1-10C alkyl optionally having branched structure, or 1-10C alkoxy optionally having branched structure;    W1=single bond, C=O, or NR129;    R129=H or 1-10C alkyl optionally having branched structure;    W2=single bond, CR130R131, C=O, O, S, SO, SO2, or NR129;    R130,R131=H or 1-10C alkyl;    R130+R131=ring;    X1,X2=single bond, 1-10C alkylene optionally having branched structure, or group of formula (vi);    R132-R135=R1;and    Y1,Y2=single bond or 1-10C alkylene optionally having branched structure.    INDEPENDENT CLAIMS are included for the following:    (1) composition containing the hyperbranched polymer and a crosslinking agent;    (2) electronic device provided with a base material and a film formed using a composition on the base material;    (3) optical component provided with a base material and the film formed on the base material;    (4) solid-state image sensor consisting of a charge coupled device or a metal oxide semiconductor integrated circuit (IC) provided with layer(s) of the film; and    (5) manufacture of hyperbranched polymer.