Transdermal administrating device

The present invention provides a transdermal administrating device capable of improving the quality of life of patients comprising an active electrode 2 having a conductive electrode layer 2a and a conductive drug layer 2b applied on the bottom surface of the conductive electrode layer, the bottom surface of the conductive drug layer 2b being capable of being placed in contact with skin 1, an inert electrode 4 capable of being placed in contact with skin and spaced from the active electrode 2, a set of conductive electrode layers 3, 3', each having a different standard single lectrode potential, a controller for measuring an internal resistance Rd of the skin tissue 1 under the region between the conductive electrode layers 3, 3' and controlling an electric current passing between the active electrode 2 and the inert electrode 4 based on the variation in the internal resistance Rd, and a dermocontact means 8 for keeping the active electrode 2, the inert electrode 4, the set of conductive electrode layers 3, 3' in contact with skin.