Disclosed is a pressure-sensitive adhesive sheet for use in processing a product such a semiconductor wafer. To provide a pressure-sensitive adhesive sheet that provides a minimized number of broken semiconductor wafers during the process of polishing them and that produces a less curl of the wafer due to the residual stress of the pressure-sensitive adhesive sheet, the pressure-sensitive adhesive sheet includes a composite film formed from a composition containing a urethane polymer and a vinyl polymer as effective components, a first film comprising a material different from that of the composite film, and a pressure-sensitive adhesive layer. It is preferable that the pressure-sensitive adhesive sheet has a modulus of 9 N/mm.sup.2 or more and 250 N/mm.sup.2 or less when an oblong piece of the pressure-sensitive adhesive sheet with a width of 20 mm is bent at a radius of curvature of 3.0 mm.