A nasal cavity insertion device fixture, whereby the displacement or detachment of a nasal cavity insertion tube is prevented during the sleep of a patient of sleep disorder. A nasal cavity insertion device fixture makes contact with the inner surface of a nasal passage in order to fix an insertion device inserted into the nasal cavity. The nasal cavity insertion device fixture preferably includes a tubular contact portion with an outer peripheral surface thereof which makes contact with the inner surface of the nasal passage. Further, the fixture for the tubular nasal cavity insertion device is preferably capable of accommodating the nasal cavity insertion tube in the inside thereof
