To provide an electroforming device which improves an electroforming accuracy without increasing a manufacturing cost, and to provide an electroforming method therefor.

This electroforming device has a cathode 109 which has a dummy face 109e opposing to an anode 102 so as to be exposed to a plating liquid ML when the cathode holds an object 105 to be electroformed. Thereby, an electric current density between an anode 102 and a cathode 109 can be changed by altering the area of the dummy face 109e, without altering an electric current supplied between them, so that the current control system in a power source 111 can be simplified.