PURPOSE: To construct a varister, having a non-linearity, fully capable of suppressing a spark discharge by ZnO and glass being composed of B2O5, BaO, ZnO, Co2O3 and Bi2O3, and having a load durability in small size fully for actual load.

CONSTITUTION: A composition is made by 30 to 70 wt% of ZnO and its binding glass of 70 to 30 wt%. And a composition of the above said glass will be made by 30 to 45 wt.pt. of B2O5, 10 to 40 wt.pt. of BaO, 15 to 40 wt. pt. of ZnO, 0.1 to 10 wt. pt. of Co2O3, 0.5 to 15 wt.pt. of Bi2O3. A glazed thick film varister in such composition is usefully applicable for a terminal voltage V10 at about 10V, nonlinear coefficient α at about 10, especially for with a low power source voltage. The varister device may be in either of lateral and longitudinal type, being constituted by substrates 1, 11, silver electrodes 2, 2' or 12, 12', and ZnO system glazed varisters 3, 13.