We have been studying metasurface reflector control based on stereo camera images. By estimating the position of each user from the stereo camera images, it is possible to consider the distance and angle of each user in metasurface reflector control without requiring channel state information, thus achieving beam division with identical received signal strength for multiple users. In this paper, we present preliminary experimental evaluation results of beam tracking using stereo camera images in metasurface reflector control at the 28 GHz band. Experiments conducted in an anechoic chamber using two human phantoms representing users confirmed the feasibility of multi-user beam tracking.