An iontophoresis device activated in use, which is capable of supplying a dissolution liquid in an amount that depends on the amount of a drug when it is used, is provided.This iontophoresis device activated in use comprises: an absorber 11 formed of a material containing a dry drug 10 and capable of absorbing a liquid; a wall material 13 disposed around the absorber 11, having an adhesive layer 12 on the undersurface thereof; a support 15 disposed on the absorber 11 and the wall material 13, having an opening 14 in the central portion thereof; an electrode 25 disposed on the undersurface of the support 15; a diaphragm 20 disposed on the support 15; and a dissolution liquid reservoir 18 disposed on the diaphragm 20, retaining a dissolution liquid for dissolving the drug between the diaphragm 20 and itself, and having a protruding portion 17 for destroying the diaphragm 20 by pressing force. The protruding portion 17 has a linear apical portion, for example, and it is disposed so that it is allowed to come into contact with or is close to the diaphragm 20. A liner 19 is removably attached on the undersurface of both the absorber 11 and the adhesive layer 12.