TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (disclosed): A silicon compound of formula: R1SiX (II), silicon compound of formula: R2SiY' (III) and silicon compound of formula: R3SiZ (IV), are mixed. A portion of the mixture is condensed by carrying out hydrolysis reaction in water in the presence of basic catalyst. The hydrolysis reaction product is re-condensed in the presence of a polar solvent, to obtain cage-type silsesquioxane compound (I).X,Y',Z=hydrolysable group chosen from halo, alkoxy, acetoxy or hydroxy.Preferred Composition: The curable resin composition further comprises unsaturated compound having (meth)acryloyl groups other than the cage-type silsesquioxane compound, ladder-type siloxane and random-type siloxane. The content of radical polymerization initiator is 0.01-10 %mass.    TECHNOLOGY FOCUS - POLYMERS - Preferred Properties: The curable resin composition is cast such that the thickness is set to 0.2 mm, and when the curable resin composition is radically polymerized by light irradiation with an accumulating exposure amount of 2000 mJ/cm2 at room temperature using a high pressure mercury lamp with an illumination intensity of 30 W/cm, the reaction rate of the (meth)acryloyl group measured by the infrared spectroscopy is 70% or more. EXAMPLE - 30 ml 5% Tetramethylammonium hydroxide aqueous solution was put into reaction container containing 120 ml 2-propanol and 150 ml toluene. Then, 66.87 g 8-methacryloyloxy octyl trimethoxysilane and 52.15 g 3-methacryloxypropyl trimethoxysilane were dripped for 30 minutes at room temperature, and stirred in the reaction container. The obtained product was stirred after completion of dripping for 2 hours, without heating. The reaction solution in the reaction container after stirring was adjusted to pH of 7 using citric acid aqueous solution. Then, pure water was added and liquid-separated to the organic phase and the water phase, 10 g anhydrous magnesium sulfate was added to the organic phase, and dehydrated. The anhydrous magnesium sulfate was separated by filtration and concentrated, to obtain 81.03 g cage-type silsesquioxane compound.