Abstract: An anaesthesia-breathing apparatus for supplying gas to a patient for artificial respiration, supported respiration, anaesthesia purposes or combinations of such purposes. The apparatus comprises a gas chamber connected to a patient connection piece, a respiratory gas receptacle, for example in the form of a respiration bag, a first check valve adapted to permit discharge of excess gas from the breathing apparatus to the atmosphere and, optionally a filter for absorption of carbon dioxide from recirculation breathing gas. Security and venting valves are not required for the patient's security during manual operation of the respiration bag because the gas chamber is in communication with the patient connecting piece via a control valve which alternately conducts exhaled gas to one end of a recirculation gas chamber or closes the communication to the recirculation gas chamber and conducts the exhaled gas from the gas chamber to the patient.