A device (1； 1') for treating the ligamentum flavum by radio frequency comprises: a hand grip (2； 2') to be held by an operator； a cannula (10； 10') fixed at its proximal end (31) to the hand grip (2； 2') and extending longitudinally from said hand grip (2； 2') to an opposed distal end of the cannula (10； 10'), designed to reach the ligamentum flavum； at least one electrode (11； 11') which is electrically connectable to a radio frequency generator and is slidably housed in the cannula (10； 10')； the cannula (10； 10') being provided with a hole (13) to allow the electrode (11； 11') to emerge from the cannula (10； 10')； an actuating device (26； 26') of the electrode (11； 11') provided in the hand grip (2； 2') for moving the electrode (11； 11'), wherein the actuating device (26； 26') comprises a slider (28； 94) along a sliding guide (27； 27') having a first (29； 91) and a second (30； 90) sliding portion placed in succession, the first portion (29； 91) being shaped so as to allow an axial translation of the slider (28； 94) along the guide (27； 27') to generate a consequent translation of the electrode in the cannula (10； 10'), the second portion (30； 90) being configured so as to allow a rotational translation of the slider (28； 94) along the guide (27； 27') so as to generate a corresponding rotational translation of the electrode (11； 11') outside the cannula (10； 10').
