A conductive layer mainly made of gold is formed on an upper surface of an insulating substrate. Plural electrodes facing each other via a gap is formed by forming the gap in the conductive layer. An overvoltage protective layer covering the gap and a portion of each of the plurality of electrodes is formed. This method can provide the gap with a narrow width precisely, and thereby, provide an electrostatic (ESD) protector with a low peak voltage, stable characteristics of suppressing electrostatic discharge, and a high resistance to sulfidation.