A varistor includes a substrate, a varistor body disposed on one surface of the substrate, first and second electrodes disposed on the varistor body and spaced apart from each other, an insulating layer disposed on at least two of the first and second electrodes and the varistor body, and first and second terminals disposed on first and second sides of the substrate opposing each other, electrically connected to the first and second electrodes, respectively, and spaced apart from each other. The substrate has mechanical strength greater than that of the varistor body.