There is disclosed a silicone-modified adamantane derivative represented by the following general formula (1), Wherein each R1 independently represents a hydrogen atom or methyl group; each R independently represents a methyl group or phenyl group; n represents an integer from 2 to 1,000; and k represents a number of 0 to 2. There can be a photo-radically curable resin composition by adopting a novel and specific silicone-modified adamantane derivative, which composition is cured by photoirradiation even at a lower intensity of illumination, thereby enabling to obtain a cured product exhibiting not only an excellent moisture resistance but also an excellent adhesiveness to various substrates.