We present an unpreceded concept, “plasma-assisted microplating”, which enable us to fabricate microelectrodes on the 3D surface. We confirm a plasma-bubble generation based on a non-conductive microhole which is a key mechanism of our proposed method. In addition, we perform in-situ microplating by the microfluidic plasma dispenser which is integrated with the generation mechanism, where Cu patterns are fabricated on a carbon tape and silicon wafer. These results indicate that our proposed method allow us to fabricate the electrodes on the surface of not only conductors but also non-conductors. Finally, we demonstrate the in-situ microplating on the UV-curing resin for 3D printing and wet sample of chicken breast. The result indicates the proposed method extend the application of 3D electrical patterning to wet samples represented by artificial/living biological tissues which is unreachable target of conventional 3D wiring techniques.