A tubular respiratory assistance device which forms the wall of a main channel and is intended to be connected by its distal end to a patient's airway, so that the main channel connects the patient's respiratory system to the outside, and which has at least one auxiliary channel which is associated with deflection means for injecting a respiratory gas jet which is deflected toward the interior of the main channel and is intended to ventilate the patient. The tubular respiratory assistance device also has an annular chamber arranged at the periphery of it, coaxially with it on its distal end, and a distal annular orifice, the annular chamber communicating with the patient's respiratory system by means of the distal annular orifice and being provided with means for connection to the outside. Also, a respiratory assistance mask intended to be fitted to a patient's face which has this tubular respiratory assistance device for inlet and outlet of respiratory gas.