Provided is a thermally conductive
silicone composition capable of both satisfying weight reduction and storage stability even when an aluminum
hydroxide filler is used. The thermally conductive
silicone composition includes: (A) a diorganopolysiloxane containing an alkenyl group bonded to a
silicon atom; (B) an organopolysiloxane having a
hydrogen atom bonded to a
silicon atom; (C) a first thermally conductive filler contained in an amount of 30 parts by
mass or more and 220 parts by
mass or less relative to 100 parts by
mass of the total amount of the component (A) and the component (B), the first thermally conductive filler being at least one thermally conductive filler selected from the group consisting of aluminum
oxide (C1) that contains less than 300 ppm of hot water-extractable
sodium oxide, as determined by atomic absorption spectrometry, and that has an average particle
diameter of less than 5 μm, and aluminum
hydroxide (C2) that contains less than 70 ppm of hot water-extractable
sodium oxide, as determined by atomic absorption spectrometry, and that has an average particle
diameter of less than 5 μm; and (D) a second thermally conductive filler contained in an amount of 400 parts by mass or more and 950 parts by mass or less relative to 100 parts by mass of the total amount of the component (A) and the component (B), the second thermally conductive filler being an aluminum
hydroxide filler that contains less than 70 ppm of hot water-extractable
sodium oxide, as determined by atomic absorption spectrometry, and that has an average particle
diameter of 5 μm or more and 100 μm or less; and (E) an
addition reaction catalyst contained in an amount of 0.2 parts by mass or more and 1.0 part by mass or less relative to 100 parts by mass of the total amount of the component (A) and the component (B).