One of the purposes of the present invention is to provide a silicone which has polymerizable groups at the both terminals and a hydrophilic side chain having three or four hydroxyl groups, is colorless and transparent and is well compatible with another monomer, particularly with hydrophilic monomer, and a method for preparing the same. The present inventor has made research to solve the afore-mentioned problems and found that a silicone represented by the formula (1), which has an unbranched or branched alkyl group represented by —CpH2p+1−q(OH) and a hydrophilic side chain containing an ether bond, has no coloration and is well compatible with other hydrophilic monomers. Therefore, the silicone polymerizes with a monomer having high hydrophilicity to give a colorless, transparent and highly hydrophilic copolymer. Further, the present inventors have found that the silicone represented by the formula (1) is obtained by addition reacting an organohydrogenpolysiloxane represented by the formula (4) with a compound represented by the formula (5).