PROBLEM TO BE SOLVED: To provide a water-containing gel sheet good in strength, stretchability, usability, skin effects, temporal stability, and the like.SOLUTION: The water-containing gel sheet 10 has a gel composition (gel layer 15) molded in a sheet-like shape. The composition comprises a component (a): a water-soluble polymer, a component (b): methyl vinyl ether/maleic anhydride copolymer, a component (c): agar, and a component (d): water, wherein the water-soluble polymer of the component (a) comprises a copolymer prepared by bonding at least (meth)acrylic acid, an alkyl (meth)acrylate, and a compound having two or more ethylenic unsaturated groups, and exhibits a thickening property, when including an electrolyte.
