A non-crosslinking type adhesive composition for an optical film is provided that has excellent adhesion to a substrate, allows peeling to be carried out at a suitable peeling strength without leaving an adhesive residue, has excellent reworking properties, can maintain good adhesion properties for a long time, and has excellent durability. The adhesive composition for an optical film includes an acrylic triblock copolymer, which does not have an NCO functional group, and an isocyanate compound. The acrylic triblock copolymer (I), which is represented by the formula A1-B-A2, is formed by alkyl methacrylate polymer blocks A1 and A2 having a Tg of 100° C. or more and an alkyl acrylate polymer block B having a Tg of −20° C. or less, wherein the content of the block B is 40 to 95 mass %, Mw is 50,000 to 300,000, and the molecular weight distribution is 1.0 to 1.5. Based on the mass of the solids in the adhesive composition, the content of the acrylic triblock copolymer (I) is 60 mass % or more, and the content of the isocyanate compound is 0.0015 mass % or more to less than 0.35 mass % in terms of NCO group content.