For the first time, experiments were carried out on the decomposition of carbon dioxide in a plasma torch maintained by continuous focused gyrotron radiation with a frequency of 263 GHz in an argon flow at atmospheric pressure. It is shown that, despite the decrease in the electron density by a factor of 5, when 3% carbon dioxide is added to the plasma-forming gas, it is possible to achieve its degree of conversion of 22% due to the nonequilibrium nature of maintaining the discharge. Thus, the prospects of using high-power electromagnetic radiation in the sub-terahertz range for solving plasma-chemical problems of the decomposition of highly stable molecules have been demonstrated. Keywords: microwave discharge, nonequilibrium plasma, gyrotron, subterahertz radiation, CO2 decomposition. Keywords: microwave discharge, nonequilibrium plasma, gyrotron, subterahertz radiation, CO2 decomposition.