Objects of the invention are to provide a hydrogel that has excellent shape stability compared with conventional technology, not only after dispensing the contained anionic reagent, but also during the anionic reagent process, and to provide an anionic reagent-containing ophthalmic device that uses this hydrogel. These objects are achieved by an anionic reagent-containing ophthalmic device containing (1) an anionic reagent, and (2) a copolymer containing, as the constituent components, a cationic monomer containing a condensate of (meth)acrylic acid and an aminoalkyl quaternary ammonium compound having a substituted or unsubstituted aralkyl group or a salt thereof, and a monomer copolymerizable therewith.本發明之目的係提供一種水凝膠，其相較於習知技術，不僅在所內包之陰離子性藥劑釋放後，於陰離子性藥劑釋放過程中亦具有優異的形狀穩定性；並旨在提供應用了該水凝膠的含有陰離子性藥劑之眼用器材。上述目的可藉由一種含有陰離子性藥劑之眼用器材等解決，該含有陰離子性藥劑之眼用器材包含：(1)陰離子性藥劑；以及(2)含有陽離子性單體、及可與陽離子性單體共聚之單體的共聚物，該陽離子性單體含有(甲基)丙烯酸與具有經取代或未經取代之芳烷基之胺基烷基4級銨化合物的縮合物或其鹽作為構成成分。
