To obtain the subject composition having strong bonding strength, and useful for adhesion of an automobile and equipment, and a permanent tightening device such as a hook for a painting, or the like by including a specific pressure-sensitive adhesive and a specified diorganopolysiloxane liquid in a specific proportion.

This adhesive composition comprises (A) a pressure-sensitive adhesive selected from the ones based on an acrylic rubber, a styrene-butadiene rubber and the like, and (B) a diorganopolysiloxane liquid having at least two hydroxyl groups per molecule bonded to silicon atom in a proportion of the component B regulated so as to be 1-20% based on the total weight of the components A and B. The component B is preferably a linear polymer of the formula; (HO)R2SiO(R2SiO)xSiR2(OH) [R is a monovalent hydrocarbyl or the like; (x) is 2-5,000], (e.g. hydroxyl-terminated dimethylpolysiloxane).