The present invention provides an adhesive hydrogel having excellent initial adhesion, and excellent adhesion while repeating use without special operation such as washing by water, and preventing rappid decrease of adhesion and stimulation of skin, and use thereof (an gel sheet and an electrode pad). The adhesive hydrogel containsing a polymer matrix comprising a copolymer constructed from monofunctional monomer and (a) crosslinkable monomer other polymer components, water and polyalcohol. At least one of the structure unit contained in the polymer matrix obtained from the monofunctional monomer and the other polymer components containing at least one structure unit selected from the group consisting of (b) an ethylene unsaturated carboxylic acid, an ethylene unsaturated carboxylate, and an ethylene unsaturated carboxylic acid derivate having hydroxyl group, acid group, the salts thereof, amino group, and/or ammonium group, the polymer components contains (c) a polymer compound having an oxyalkylene group or polyoxyalkylene group as a side chain.本發明提供具備初期黏著力優異,且不需伴以水洗等特殊操作,重複使用之際,具有優異之黏著力,同時可抑制重複使用時黏著力之快速降低及對於皮膚之刺激等之黏著性水凝膠及其用途(水凝膠片及電極墊板)。該黏著性水凝膠係含有:包含單官能基單體與(a)交聯性單體之共聚物之高分子基體、其他高分子成分、水、以及多元醇之黏著性水凝膠。上述高分子基體中所含有之源自上述單官能基單體之構成單元及上述其他高分子成分中至少一者係含有至少一種選自(b)乙烯性不飽和羧酸及乙烯性不飽和羧酸鹽,以及具有羥基、酸基、其鹽、胺基及/或銨基之乙烯性不飽和羧酸衍生物所組成群組中之構成單元,而上述之其他高分子成分係含有(c)具有氧伸烷基或聚氧伸烷基支鏈之高分子化合物。
