A voltage variable resistor comprising a sintered wafer consisting essentially of zinc oxide (ZnO) and, as an additive, lanthanum oxide (La2O3) and/or yttrium oxide (Y2O3) and two electrodes applied to opposite surfaces of said sintered wafer, at least one of said two electrodes being a silver paint electrode. The voltage variable resistor modified with lanthanum oxide (La2O3) and/or yttrium oxide (Y2O3) has the electrical properties thereof improved by the further addition of cobalt oxide (CoO) and manganese oxide (MnO).