A varistor includes a ceramic substrate having an insulating property, a varistor layer provided on the ceramic substrate and mainly containing zinc oxide, a first glass ceramic layer provided on the second surface of the varistor layer, first and second internal electrodes provided in the varistor layer and facing each other. The varistor has a small, thin size, and has sufficient varistor characteristics against surge voltages. The varistor provides a small electronic component module with resistance to static electricity and surge voltages.