There is provided a hydrated adhesive skin patch that keeps viscosity even after moisture in an adhesive layer evaporates.A hydrated adhesive skin patch to be combined with an acrylic acid alkyl ester copolymer in an adhesive layer, the acrylic acid alkyl ester copolymer being the copolymer of a monomer mixture comprising monomer A and monomer B. The monomer A is a polymer where a glassy-transition temperature (Tg) is 270K or more when the monomer A is homopolymerized while the monomer B is a polymer where a glassy-transition temperature (Tg) is 220K or less when the monomer B is homopolymerized. The ratio of the monomer A is 30 mass% or more and 50 mass% or less relative to the whole mass of the monomer mixture.本發明之課題在於提供一種即便於黏著劑層中之水分揮散後，黏著力亦能持續之含水系貼附劑。本發明之含水系貼附劑係將如下丙烯酸烷基酯系共聚物調配至黏著劑層而成，該丙烯酸烷基酯系共聚物係包含單體A與單體B之單體混合物之共聚物，且上述單體A於使該單體A均聚時會成為玻璃轉移溫度(Tg)為270 K以上之聚合物者，上述單體B於使該單體B均聚時會成為玻璃轉移溫度(Tg)為220 K以下之聚合物者，且相對於上述單體混合物之總質量，上述單體A之比率為30質量%以上50質量%以下之比率。
