PROBLEM TO BE SOLVED: To provide an ocular lens having high transparency in spite of copolymerization with a hydrophilic monomer and is capable of exhibiting high oxygen permeability and high wettability with water by incorporating a monomer for the ocular lens expressed by a specific formula as a polymerization component therein. SOLUTION: The monomer for the ocular lens expressed by the formula is incorporated as the polymerization component into the monomer for the ocular lens and a polymer for the ocular lens to be adequately used for the ocular lenses, such as contact lenses and artificial corneas. In the formula, X denotes a group selected from N-Y, O and S Y denotes H and a substituent selected from 1-20C alkyl groups and 6-20C aryl groups R1 denotes a group selected from H and a methyl group R2 denotes H and a substituent selected from 1-20C alkyl groups and 6-20C alkyl groups. When X denotes N-Y, Y and R2 may formed a ring including N by bonding each other (n) denotes an integer of 0 or 1 and R2 denotes a 1-20C alkyl group substituted by a siloxanyl group.
