A peroxide curable silicon adhesive composition comprising a diorganopolysiloxane (A), a polyorganosiloxane (B) comprising R.sup.1.sub.3SiO.sub.0.5 unit and SiO.sub.2 unit in a molar ratio of the R.sup.1.sub.3SiO.sub.0.5 unit to the SiO.sub.2 unit of from 0.6 to 1.7, a hindered amine compound (C), and an organic peroxide (D), and an adhesive tape thereof are provided. Also provided are an addition-reactive silicon adhesive composition comprising a diorganopolysiloxane (A') having 2 or more alkenyl groups, a polyorganosiloxane (B), a hindered amine compound (C), a polyorganosiloxane (E) having SiH group, a retarder (F), and a platinum catalyst (G), and an adhesive tape thereof.