The present invention relates to a pressure-sensitive adhesive sheet for dicing, which comprises a substrate and at least one pressure-sensitive adhesive layer disposed on at least one surface of the substrate, the substrate containing polyvinyl chloride as a primary component and a trialkyl phosphite as a thermal stabilizer of the polyvinyl chloride, and the pressure-sensitive adhesive layer containing poly(meth)acrylic acid ester as a primary component, in which the trialkyl phosphite transited from the substrate into the pressure-sensitive adhesive layer is not unevenly distributed on a surface of the pressure-sensitive adhesive layer; a method of processing a processed material using the same, and a piece of a processed material obtainable by the method.