To provide a self-adhesive heat radiation sheet more inexpensive than a silicon resin having hardness endurable in impact and self adhesion force capable of adhesion itself while having excellent thermal conductivity and absorbing a difference between the thermal expansions of a heat radiation plate and parts.

The self adhesive heat radiation sheet comprises an urethane resin gel composition formed by the reaction with hydroxypolyol containing at least one or more hydroxyl groups, a polyol component mixing a plasticizer and thermal conductivity giving agent and isocyanate compound, concretely, the self adhesive heat radiation sheet comprises the urethane resin gel composition formed by the reaction with the polyol component mixing the plasticizer of 50 pts.wt. or more and mixing the thermal conductivity giving agent of 100 pts.wt. or more to hydroxypolyol of 100 pts.wt. containing at least one or more hydroxyl groups and the isocyanate compound having 80 or more of an isocyanate index.