An iontophoresis device for administering drug ions via the first
ion-exchange membrane, comprising a first semi-permeable film having a
number of pores passing through the film from a front surface to a back
surface, a first ion-exchange membrane formed of ion-exchange resin
filling the pores of the first semi-permeable film and selective ions of
a first polarity, and a working electrode structure having a drug holding
part placed on a back surface of the first ion-exchange membrane and
holding a drug solution containing drug ions charged in the first
polarity, wherein a layer of a water-soluble polymer compound is
chemically bonded on the surface of the first semi-permeable film.