<p>[Problem] To provide a device for otorhinolaryngological treatment whereby an extension body can be easily aligned within the nasal cavity without the need for X-ray viewing. [Solution] A device for the treatment of sinusitis has: a flexible long body (11) inserted into the paranasal sinus via the nasal cavity; an extension body (12) provided to the long body (11), the extension body having an active extension part (12a) for extending and deforming in the radial direction in the natural orifice located between the nasal cavity and the paranasal cavity and for expanding the constricted part of the natural orifice; and an imaging means (13) for acquiring an image to the front of a distal end of the long body (11), the imaging means being provided integrally with the long body (11) closer to the distal side on the long body (11) than the extension body (12).</p>
