New superconductors under very high pressure

We have developed extreme conditions combining very low temperature and very high pressure of down to 30 mK and up to 200 GPa, respectively. These conditions are realized by using a DAC (diamond-anvil cell) which we designed for assembly on a powerful He-3/He-4 dilution refrigerator. Using these apparatus and techniques, we have searched for pressure-induced superconductivity in various materials, especially in elements under pressure. Here our experimental techniques and experimental results are reviewed.