Abstract: The high-voltage circuit breaker with gas insulation is equipped with a device for gas-blast and blowout of the arc generated between the stationary arcing contact and the movable arcing contact when the current is interrupted. Downstream from the blowout nozzle there is located a cooling tube provided with several holes for flow of the gas placed on the outlet path of the hot gas generated by the arc. When the hot gas flows in the cooling tube, the gas pressure difference at the level of the outlet holes causes cool gas to be sucked into the tube and gives rise to a mixture of the hot and cold gases. The gas outlet to the outside of the cooling tube is sufficiently cooled to ensure the dielectric characteristics of the circuit breaker.