[Problem] To provide a skin adhesive sheet which has good adhesion to the surface of skin, is hardly dried even when used for a long period, can keep flexibility thereof, and rarely undergoes the change in shape. [Solution] A skin adhesive sheet which comprises a copolymer containing components A and C as mentioned below as polymerization components and has a water content of less than 10% by mass. Component A: a polysiloxane macromonomer which has multiple polymerizable functional groups per molecule and has a number average molecular weight of 6000 or more. Component C: a polymerizable monomer which has an alkyl group and has no fluoroalkyl group.