This paper deals with a self-organizing robotic system that consists of a number of autonomous robots. We describe the idea of sociery of robots, which is based on decentralized autonomous systems such as human being or insects. As one of the se[forganizing robotic systems, cellular robotic system (CEBOT) was proposed by T.Fukuda. The cellular robotic system is one of the distributed robotic systems, which is composed of a number of autonomous robotic units called cells. The cell is a fundamental unit that has a simple function. To carry out given tasks, the cells connect each other and cooperate mutually. This paper denotes the concept of the cellular robotic system (CEBOT), the social organization of robotic systems, and evolution of group system.