Abstract: The present invention relates to an iontophoresis system. A power supply circuit for applying pulsating voltages to iontophoretic elements includes an element selector and a potential difference generating unit. The element selector selects a combination of iontophoretic elements according to given timing. The potential difference generating unit generates a potential difference between a selected combination of iontophoretic elements by applying pulsating voltages to the iontophoretic elements at different time periods. When the system is in operation, the iontophoretic elements will not be kept at a certain potential and undesirable electrode reactions can be prevented from occurring at each iontophoretic element.