A respirator device especially for the respiratory treatment of new-born and inmate infants and for their adaptation to natural breathing. The device comprises oxygen and air ducts, means for adjusting the composition, temperature, humidity, and other parameters of the gas mixture, a patient junction, and pressure adjusting valve means coupled to the junction shunting the gas flow in the junction in such a way that the gas pressure is positive both during expiration and inspiration.The respiration demand of the patient is sensed by a means responsive to pressure drops which controls a starting signal generator and a beat generator. The beat generator controls the valve means. The device can be adjusted to controlled respiration, controlled assisted respiration, inspected and assisted respiration, and continuous positive airway pressure modes, whereby it can be adapted to various respiratory diseases. In the inspecting modes a respiration stoppage detector senses the spontaneous inspirations and in response to a stoppage exceeding a predetermined waiting period, performs controlled respiration for a given period of time and starts an alarm.