PURPOSE: To obtain the title lens having a high moisture content and a large tensile strength by incorporating a copolymer composed of dimethyl acrylamide, a hydrophobic monomethacrylate and a specific cross-linking agent to the title lens.

CONSTITUTION: The contact lens having ≥60% moisture content comprises copolymer of 50W85wt% dimethyl acrylamide, 15W50wt% at least one of the hydrophobic monomethacrylate and 0.3W3.0wt% cross-linking agnt. The cross linking agent is preferably dimethacrylate having a some extent of a molecular length. If the ordinary cross-linking agent such as ethylene glycol dimethacrylate and divinylbenzene having a short molecular length is used, said cross-linking agent does not contribute to the improvement of the tensile strength of the polymer contg. the high moisture. While, the cross-linking agent having a very long molecular chain such as polyethylene glycol dimethacrylate, for example, ethylene oxide 14mol adduct, does not remarkably improve the strength of the polymer contg. a high moisture.