A simple but convenient method for fabricating ZnO micro-sized structure selectively and artificially between two micron-gap electrodes was proposed and investigated. The technique is based on electrolytic deposition in aqueous solution of zinc nitrate or zinc acetate, which selectively occurs between the electrodes being enhanced by electric field. The deposition characteristics were investigated in terms of the deposition conditions, and under the optimized condition ZnO micro-sized structure was obtained with bridging between the electrodes. The gas sensing characteristics of the structure was investigated by exposing to a 500 ppm H2 gas, resulting in 23% variation of the resistance at room temperature. The device dimensions can be downsized to nanometer scale by applying nano-gap electrodes, and therefore this technique is promising for fabrication of highly functional nano-sized sensors at low cost, contributing to mass applications.