The present invention verifies a method for alleviating dermal irritation (in particular, cumulative dermal irritation) when a local anesthetic is administered by transdermal iontophoresis, and provides an electrode pad imparting greater safety, not only during single-dose administration but also during repeated-dose administration, for pain relief of pain upon injection. An iontophoresis electrode pad comprises: a sheet base material (1)； an electrode (3) disposed above the sheet base material； an adhesive sheet (2) provided with an opening, the adhesive sheet being disposed above the sheet base material in a state where the electrode is exposed within the opening； and a drug reservoir (4) containing a local anesthetic, the drug reservoir being disposed in a state of contact with the electrode within the opening of the adhesive sheet. The present invention avoids contact with the skin in a state where the inner peripheral surface of the opening of the adhesive sheet (2) and the outer peripheral surface of the drug reservoir (4) are abutting, and thereby provides relief for dermal irritation.
