current with respect to the change in voltage is smaller than that of the comparative examples in other words the embodiment has such robust properties that current is stable under variations in the applied voltage in the first embodiment it is thought that production of the above described unequal electric field concentrating at the tip of each serration generates stable discharge as a whole the discharge voltage is therefore reduced and there is no torricelli pulse as the results of measurement discharge occurs in a range from 10 to 28 kv and is glow corona discharge stably maintained without producing trichel pulses moreover as described above the slope of the change in discharge current with respect to the change in applied voltage is small and the robust properties are ensured in a second embodiment the electrode 10 a has a blade shaped tip and is combined and paired with a 100 m u03c9 resistor having the same diameter as that of the electrode 10 a fig1 is a perspective view illustrating the appearance of the electrode section 10 of the second embodiment fig1 a is a side view of the electrode section 10 of the second embodiment and fig1 b is a cross sectional view in the second embodiment the electrode section 10 includes a pair of the blade shaped electrode 10 a and 100 m u03c9 resistor 10 c which are combined and joined with a screw 10 d the blade shaped electrode 10 a is different from the blade shaped serrated electrode 10 a of the first embodiment only in including no serrations the dimensions of the blade shaped electrode 10 a are the same as those.