Iontophoresis device

An iontophoresis device having a working electrode structure, said working electrode structure comprising:

• a first electrode;
• a biological interface contact member including a substrate having a front surface and a rear surface, and a plurality of needles that protrude from the front surface of the substrate and can be inserted into a biological interface, the biological interface contact member allowing selective permeation of ions of a first polarity;
• and
• a drug holding part applied with an electrical potential through the first electrode and holding a drug solution containing drug ions charged in the first polarity, the drug holding part being interposed between the first electrode and the biological interface contact member.