Superconductors having critical temperatures close to room temperature under high pressure are reported recently. We can expect, if a room-temperature superconductor (RTS) is realized, it will greatly contribute to the future of mankind as a highly energy-saving and highly functional material. Removing the requirement of high pressure seems not easy. However, from a different point of view, the fact that RTS can exist even at high pressure is an important fact that led us to investigate further material synthesis and development. In this paper, the latest research themes under high pressure, not limited to RTS are reviewed.