Results of studies on the anodic oxidation of SO32- ions in the diaphragm electrolyser for the 30% H2SO4 solution are presented. Effect of the anode surface development, initial concentration of sulfate(IV) ions, solution flow rate through the anode, and current density on the current efficiency of the oxidation process and unitary consumption of the electric energy is determined. Recommended conditions of the electrochemical oxidation of sulfuric(IV) compounds to sulfuric acid(VI) for the utilization of sulfur dioxide from off-gases of sulfuric acid production are given.