Abstract: A device for burning premixed gas, including a ventilator (1) for drawing in the air/gas mixture, a gas-supply valve (2), a gas injector (3), and a venturi (4) interposed between said injector (3) and the ventilator (1), so as to create a negative pressure on the gas valve (2), The venturi (4) includes a movable part (40) capable of moving under the action of said ventilator (1) and a restoring spring (43), the displacement of said movable part being capable modifying the cross-sections of the passages (41, 42) for gas (G) and air (A).