This paper presents the design of multi-robots or multiple mobile sensors and gives the results of the team behavior of them in a potential field in a collaborative manner. The aim is to prove the concept of the fractal conductivity-based approach to mobile sensor networks in a potential field. We attempted to create multi-robots having similar inherent nature, similar background knowledge, and the same mission as relevant bodies, the creation of some sort of attraction force between them is achieved with the application of fractal conductivity of belief functions. We attempted to develop multi-robots capable of carrying out an orchestrated movement in an environment having some kind of potential field such as a chemical substance contaminated into sea or lake water. The basis of the theory of behavior in a potential field is established. The fractal conductivity approach is explained. A mobile sensor structure having an input, output, and internal belief functions is designed. Internal structures of mobile sensors are implemented by software. A mobile sensor network composed of mobile sensor nodes is developed. Two communities of interest groups have been constituted. Collaborative behaviors of multi-robots in a potential field are investigated. The mobile sensors move towards a target by sensing the potential field at their locations, broadcasting the information composed of locally sensed intensity of the potential field around them and the infrastructure knowledge of themselves to other sensors and receiving the information of the potential field intensities together with the identity information that is being broadcasted from the other mobile sensors inside the potential field. The target is a source creating the potential field. A mobile sensor is a body incorporating a prior knowledge base that is the identity information in the form of a fractal belief function inside itself. After developing the theoretical basis for sensing potential field and movement, a fractal conductivity approach, which is based on fractal natures of the belief functions, is applied to this basic approach to obtain the movements of the multi-robots as a coordinated team, i.e., grouped as relevant bodies. The operation of mobile sensors based on time division multiple access method is achieved. The results of coordinated movement and obstacle avoidance have been demonstrated by the simulation results.