Advantages of 3D-TEM/electron tomography are described for development of rubber science and technology. The first result of visualization of carbon black (CB) network is shown, which was obtained by combining 3D-TEM/electron tomography and electric characteristic measurements. A novel analysis for characterization of the CB network is proposed on the basis of gelation mechanism of polymer network, where structural parameters of crosslined and branched chains of CB aggregates are determined by 3D-TEM/electron tomography and are utilized. Good relationships between the CB network structures and electrolytic properties are also shown in this review paper.