Disclosed is an electrode device for iontophoresis, wherein an electrode layer for drug introduction can be firmly bonded to a drug reservoir layer by a simple means and the drug reservoir layer can be stably held at the time of drug introduction.Specifically, a main electrode layer (3) and an auxiliary electrode layer (1) are affixed on a substrate (6), while being insulated from each other. The main electrode layer (3) is used for drug introduction, and the auxiliary electrode layer (1) is provided for the purpose of holding a drug reservoir layer (5) on the substrate (6). The drug reservoir layer (5) is arranged on the substrate (6) so as to be in contact with the main electrode layer (3) and the auxiliary electrode layer (1). The drug reservoir layer (5) is composed of a gel that contains a halogen compound, and the auxiliary electrode layer (1) is configured of a metal that has lower ionization tendency than hydrogen. By passing an electric current between the drug reservoir layer (5) and the auxiliary electrode layer (1), the two layers are affixed to each other. As a result, the drug reservoir layer (5) can be firmly held on the substrate (6), while being in contact with the main electrode layer (3).
