Filled rubbers are mixtures of polymers having low glass transition temperatures and inorganic fillers such as carbon black. Nanoparticle-filled rubbers include hierarchical network structures i.e. entanglement, bridged filler, and contact filler networks, due to polymer-polymer, polymer-filler, and filler-filler interactions, respectively. In this article, change in hierarchical network structures of filled rubbers in mixing and kneading processes are discussed from the viewpoint of Three Network Model.