A silicone adhesive composition includes 100 parts by weight of a peroxide-curable silicone, 1.2 to 3.2 parts by weight of an organic peroxide curing agent, and 2 to 9 parts by weight of an addition reaction-curable silicone rubber. An adhesive tape includes a base and an adhesive layer placed on the base, the adhesive layer being formed from the above silicone adhesive composition. The adhesive composition exhibits high load bearing capacity even in higher-temperature environments than ever before. The adhesive tape exhibits high load bearing capacity and good shelf life even in such high-temperature environments.