We isolated an aerobic autotrophic bacterium from a hot spring on Kunashir Island and identified it as Thermus brevis strain PS18 cells were short straight nonmotile rods, 0.5x1.0-1-2 mkm. Strain PS18 grows autotrophically aerobically with thiosulfate (electron donor) and O₂ (acceptor). Autotrophy has been previously unknown in representatives of the Deinococcota phylum. Autotrophic growth of PS18 under aerobic and anaerobic conditions was characterized in growth experiments by proteomic analyses.