A helmet (10) for non-invasive ventilation of patients comprising:a container body (20) in which there can be housed the head of a patient, provided with at least one optically transparent portion and with an open end to which a first rigid ring (21) is fixedan elastically yieldable collar (30) which can be sealingly coupled to the neck of the patient and fixed to a second rigid ring (31) can be sealingly removably associated to said first rigid ring (21),whose distinguishing characteristic consists in comprising a bayonet-like coupling means adapted to removably couple the first and the second rigid ring with respect to each other (21,31).
