A single or multiple cutters are pressed against end surfaces of a resistive element so as to form a plurality of notches in rims of the end surfaces. At this time, notches are formed such that notch depth at the end surfaces of the resistive element toward the axis center is smaller than notch length from the end surfaces of the resistive element to the axis. This allows easy cutting and removal of the resistance wire at the resistive element ends of a coil resistor, etc., and prevention of fraying of a wound wire at the resistive element ends.