Smooth motion of the visual stimuli created by the random dot kinematograms (RDK) evokes magnetic fields from the human extrastriate cortex. We investigated whether the speed of RDK affects the peak latency of the magnetic responses from five healthy subjects. Speed of random and coherent motion consisted of three levels; low (L): 0.6? s^-1, medium (M): 9.6? s^-1 and high (H): 25? s^-1. The magnetic responses to all stimulus conditions were composed of one to four components depended on the subjects and stimulus conditions. In this study we concentrated on only the peak latencies of the first components. The speed of the random or coherent motion of the RDK after the trigger pulse did not affect the latencies when these stimuli were followed by the stationary random dots. The latencies, however, were inversely related to the speed of the random motion of RDM before the trigger pulse no matter what the stimulus condition of RDK after the trigger pulse. Estimated origins of the first components were always in the same area, around the meeting point of the ascending limb of the inferior temporal sulcus and the lateral occipital sulcus. The results suggest that the random motion of the RDK is most effective stimulus to the neural activities in the visual motion area. The physiological significance of the results will be discussed with recent studies with mokeys and humans.