An object of the invention is to provide an adhesive composition for skin that gives an adhesive for skin that can be coated readily and is highly cohesive and also an adhesive for skin and an adhesive sheet for skin prepared by using the adhesive composition for skin.Provided is an adhesive composition for skin including a radiation-curable resin and a reactive diluent that reacts with the radiation-curable resin. The adhesive composition for skin gives an adhesive for skin that can be coated readily and is highly cohesive. Also provided are an adhesive for skin prepared by irradiating the adhesive composition for skin with radiation and an adhesive sheet for skin including a base sheet and an adhesive layer of the composition for skin formed thereon.