A thermally conductive resin composition capable of maintaining high thermal conductivity and a thermally conductive sheet using the same, a thermally conductive resin composition contains an addition reaction type silicone resin, a thermally conductive filler, an alkoxysilane compound, and a carbodiimide compound in which a subcomponent is in an inactive state with respect to an alkoxysilane compound, and contains 55 to 85% by volume of the thermally conductive filler. A thermally conductive resin composition contains an addition reaction type silicone resin, an alkoxysilane compound, a thermally conductive filler, and a carbodiimide compound in which a subcomponent is in an inactive state with respect to the alkoxysilane compound, and exhibits thermal conductivity of 5 W/m*K or more after curing.