In this paper, a novel wireless functional electrical stimulation (FES) device based on an ergodic cellular automaton (CA) central pattern generator (CPG) is proposed, where the CPG consists of a network of ergodic CA oscillators coupled via wireless impulse radio (IR) sequences. It is shown that the proposed CPG can realize various synchronization phenomena by adjusting parameters. In addition, an electric stimulator controlled by a novel pain relaxation filter is proposed. Then the proposed wireless FES device is implemented and human subject experiments reveal that the device can assist periodic motions of arms for walking and squatting. It is also shown that the pain relaxation filter can decrease the pain caused by the electric stimulation. Furthermore, it is shown that the proposed CPG can be implemented by fewer circuit elements and consumes lower power compared to a conventional digital-processor-based CPG. Finally, it is discussed that the results of this paper will contribute to the development of a large-scale, small, and low-power wireless FES device to support a variety of body movements.