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 chemically bonded on the surface of the first semi-permeable film.