[Problem] To make the field of vision for a part to be observed clear, and to enable the operation of a treatment to progress smoothly without causing the accumulation of a mucosal fluid or a washing fluid in a nasal cavity.[Solution] A method for treating a symptom of rhinitis surgically, comprising: a step of inserting a tip part of an endoscope (10) and a tip part of a tubular fluid path constituent member (30) that is so arranged on an insertion part (12) as to surround the outer peripheral surface of the insertion part (12) into a nasal cavity a step of partitioning a space formed between the fluid path constituent member (30) and the outer surface of the insertion part (12) into a fluid supply gap and a fluid discharge gap, supplying a washing fluid to the fluid supply gap from the outside of the nasal cavity, introducing the washing fluid into the inside of the nasal cavity, and discharging the washing fluid in the nasal cavity into the outside of the nasal cavity through the fluid discharge gap together with a dirty fluid in the nasal cavity a step of inserting a surgical probe into the nasal cavity a step of exposing a posterior nasal nerve from a surrounding tissue by means of the supply and discharge of the washing fluid under the observation on the endoscope (10) and a step of severing the exposed posterior nasal nerve with the surgical probe while separating the posterior nasal nerve from the surrounding tissue.Linvention a pour but de rendre le champ de vision pour une partie à observer net, et de permettre à lopération dun traitement dévoluer sans à-coups sans entraîner laccumulation dun fluide mucosal ou dun fluide de lavage dans une cavité nasale. A cet effet, linvention concerne un procédé de traitement de symptôme de rhinite de façon chirurgicale, comprenant : une étape consistant à introduire une partie de pointe dun endoscope (10) et une partie de pointe dun élément constitutif dun trajet de fluide tubulaire (30) qui est agencé sur une partie di
