A heat-conductive silicone grease composition comprising (A) an organopolysiloxane in an amount of 20 to 90 parts by mass, (B) a non-silicone-type organic compound in an amount of 80 to 10 parts by mass (wherein the total amount of the components (A) and (B) is 100 parts by mass) and (C) a heat-conductive inorganic filler having an average particle diameter of 0.5 to 100 μm in an amount of 200 to 2,000 parts by mass relative to 100 parts by mass of the total amount of the components (A) and (B), wherein the SP value of the non-silicone-type organic compound (B) is greater than that of the organopolysiloxane (A) (i.e., (B)>(A)), the value obtained by subtracting the SP value of the component (A) from the SP value of the component (B) is greater than 2, and the viscosity of the heat-conductive silicone grease composition is 50 to 1,000 Pa·s at 25° C.