When multiple robots cooperate within same environment, collision avoidance is essential technology for each robot. In order to achieve effective collision avoidance, it is desired to recognize surrounding robot's motion each other. For this purpose, it is appropriate to exchange motion information by inter-robot communication. In this paper, we propose a local communication system for collision avoidance based on inter-robot communication. By rotating a transmitter and a receiver using a motor, spatially seamless communication toward every direction of robot's surroundings is achieved, and spatial resolution of transmission information which changes according to transmitting direction is also improved. We introduce wireless power supply system to rotary transmitter and receiver. Finally, we conducted experiments to confirm performance of the wireless power supply system and communication quality of the local communication system.