An iontophoresis patch is equipped with a donor gel and a reference gel which are disposed to contact an external conductor, for example, the skin of a patient and thereby output current from a current-carrying device to the external conductor. The iontophoresis patch includes: a donor portion having the donor gel containing a medical agent to be penetrated into the external conductor a reference portion having a reference gel, mounted with the current-carrying device on the surface on the side opposite to the reference gel, and disposed on the external conductor apart from the donor portion and an electrode film for supplying current from the current-carrying device to the donor gel and the reference gel.
