Tokamak plasma research has been carried out for more than forty years. Small size tokamaks with major and minor radii of ˜0.3 m and ˜0.1 m were built and used in early experiments, and led the tokamak research to its present successful status involving large tokamaks such as the JT-60U and JET. The role of small tokamaks may have changed, but they still contribute to the understanding of tokamak physics and to the development of tokamak technology. Here, some experimental studies using small tokamaks are shown.