Herein disclosed is an iontophoresis device suitable for effective use of a drug supported on a drug support. A donor electrode-printed portion (6) and a reference electrode-printed portion (7) are arranged on a backing layer (4). The backing layer is provided with, at the periphery, an adhesive film (3) for fixing a pharmaceutical preparation to an application site. The both electrode-printed portions (6), (7) are electrically connected to a current-generating portion (Ia) through a conductive snap connector (Id). The drug support (14) is removably joined with a conductive layer (11) formed on the electrode on the side of the donor electrode-printed portion (6). The drug support (14) is subjected to a drug diffusion-inhibitory treatment (30).