The present invention discharges liquid in a straight line even when the electrode remains retracted. Provided is a high frequency treatment instrument (1), which is equipped with a long narrow tubular sheath (2), an electrode member (3) that is advanced and retracted with respect to the tip of the sheath, and a liquid supply means for supplying liquid in a flow channel inside the sheath towards the tip, wherein: the tip of the electrode member is provided with an expanded tip section (3b) with a basal end face (3c), the expanded tip section extending radially outward and being advanced and retracted with respect to the tip of the sheath the sheath is provided, at a position in which at least a portion of the expanded tip section is accommodated inside the sheath, with a restricting section (6e) for restricting the movement of the electrode member towards the base end and an accommodating section (6d) capable of accommodating at least a portion of the expanded tip section and at the position in which at least a portion of the expanded tip section is accommodated inside the sheath, after liquid that has been supplied via the flow channel collides with the basal end face of the expanded tip section and is made to flow radially outward, the liquid collides with the inner circumferential surface of the accommodating section and is discharged from a discharge opening formed between the expanded tip section and the inner circumferential surface of the accommodating section.La présente invention évacue le liquide suivant une ligne droite, même lorsque lélectrode demeure rétractée. Linvention concerne un instrument de traitement par haute fréquence (1), qui est équipé dune longue gaine tubulaire étroite (2), dun élément délectrode (3) qui est avancé et rétracté par rapport à la pointe de la gaine, et un moyen dalimentation en liquide pour amener du liquide dans un canal découlement à lintérieur de la gaine en direction de la pointe, où : la pointe de lélément délectrode est
