The present invention verifies a method of reducing skin irritation (particularly, cumulative skin irritation) caused by transdermal administration of a local anesthetic using iontophoresis, and provides an electrode pad for relief from a puncture pain which is safe not only at single administration but also at repeated administrations. The electrode pad comprises a base sheet; an electrode placed on the base sheet; an adhesive sheet placed on the base sheet and having an opening, within which the electrode being exposed; and a medicament reservoir containing a local anesthetic and placed in the opening of the adhesive sheet while being in contact with the electrode. An inner peripheral surface of the opening of the adhesive sheet and an outer peripheral surface of the medicament reservoir are prevented from coming into contact with human skin while contacting with each other, and thereby skin irritation is reduced.