Electrorheological (ER) finishing utilizes the flow of electrically stiffened abrasive fluid through a preset converging gap formed by the work-piece surface and a moving tool. An ER finishing tool characterized by cathode integrated with anode together is proposed, whose electric field distribution is finite-element-analyzed (FEA) and is useful to finish both conductive work-piece and non-conductive ones. Experiments were performed to finish a K9 glass by this tool. After 30 minutes polishing, the surface roughness was reduced from 8.46 to 2.53 nm Ra which is better than previously reported 2.9 nm. The result verified the validity of the integrated-electrodes tool for non-conductive optical glasses.