Abstract: A device for injecting and igniting a fuel in a flow of air, comprising a bular duct in which are generated an internal flow of rotating air and an intermediate flow containing fuel which is sandwiched between the internal flow and an external flow of rotating air, in which ignition is effected by a central electrode placed in the axis of the tubular duct and defining within the latter an annular channel which narrows around the downstream end of the central electrode to form an annular gap of uniform width along the entire extent of its circumference, in such a way that a difference in electrical potential applied between the electrode and the tubular duct causes sparks to jump between the free end of the electrode and the tubular duct across the internal flow and the intermediate flow.