An oxidized edge surface of pyrolytic graphite (PG) has been prepared by electrochemical treatment. A thin layer of poly(vinyl chloride) (PVC) was coated on the oxidized edge surface, and the PVC-coated sample heat treated at 300, 400, and 500 degrees C, respectively. The influence of the PVC coating on the structural change of the oxidized ledge surface of PG caused by the heat treatment was studied by laser Raman and Fourier transform-infrared attenuated total reflection spectroscopies. For the electrochemical treatment, the formation of oxygen-containing functional groups proceeds over the edge surface of PG. With increasing degree of oxidation, the functional groups are formed in the following order; hydroxyl groups, carboxyl groups, lactone groups, quinones, and acid anhydrides. Acid anhydrides are formed on the outermost surface and completely eliminated by heat treatment up to 300 degrees C. The other functional groups remain even after heat treatment up to 500 degrees C. However, the functional groups are eliminated by the PVC coating, the elimination temperature depending on the type of functional groups : quinones, lactone groups, and carboxyl groups are eliminated at 300, 400, and 500 degrees C, respectively. PVC coated on the edge surface is found to play an important role in the complete elimination of oxygen-containing functional groups with > C=O through heat treatment at 500 degrees C.