Recently, the study of Ubiquitous Robot(UR) is one of the hot topics in robotics field. The UR system can support several types of robots and mobile robots from an environment. Moreover, human can also be supported by UR system. Each device is independently distributed in UR environment. When these devices are controlled such like feedback control, time synchronization is one of the important technologies for the control. In this paper, the wireless time synchronization module is proposed as one of the solutions of time synchronization for distributed devices, and evaluated through the experiment.