Device (1; 1') for treating the ligamentum flavum by radio frequency, comprising: - a hand grip (2; 2') to be held by an operator, said hand grip (2; 2') having a body designed to be grasped by the operator, - a cannula (10; 10') fixed at its proximal end to said hand grip (2; 2') and extending longitudinally from said hand grip (2; 2') to an opposed distal end of the cannula (10; 10'), said cannula (10; 10') being arranged for reaching said ligamentum flavum; - at least one electrode (11; 11') which is electrically connectable to a radio frequency generator and is slidably housed in said cannula (10; 10'); - said cannula (10; 10') being provided with a hole to allow said electrode (11; 11') to emerge from said cannula (10; 10'); - an actuating device (26; 26') of said electrode (11; 11') being provided in said hand grip (2; 2') for moving said electrode (11; 11'), wherein said actuating device (26; 26') comprises a slider (26; 94) slidable along a sliding guide (27; 27') and arranged for being actuated by an operator so as to be moved along said sliding guide to progressively push said electrode through the hole so as to make the electrode (11; 11') progressively emerge from the cannula (10; 10') to an operative configuration, wherein the actuating device further comprises a cavity defined on the body at the sliding guide and designed to cooperate therewith to direct the sliding of the slider, said cavity comprising a first (29; 91) and a second sliding portion (30; 90) placed in succession and positioned side-by-side along the longitudinal axis of the body and defining two adjacent and successive sliding portions for the slider, - said first portion (29; 91) being shaped so as to allow an axial translation of said slider (28; 94) along said guide (27; 27') to generate a consequent translation of said electrode in said cannula (10; 10'), and said second portion (30; 90) being configured so as to allow a rotational translation of said slider (28; 94) along said guide (27; 27') so as to generate a corresponding rotational translation of said electrode (11; 11') outside said cannula (10; 10'). - a hand grip (2; 2') to be held by an operator, said hand grip (2; 2') having a body designed to be grasped by the operator, - a cannula (10; 10') fixed at its proximal end to said hand grip (2; 2') and extending longitudinally from said hand grip (2; 2') to an opposed distal end of the cannula (10; 10'), said cannula (10; 10') being arranged for reaching said ligamentum flavum; - at least one electrode (11; 11') which is electrically connectable to a radio frequency generator and is slidably housed in said cannula (10; 10'); - said cannula (10; 10') being provided with a hole to allow said electrode (11; 11') to emerge from said cannula (10; 10'); - an actuating device (26; 26') of said electrode (11; 11') being provided in said hand grip (2; 2') for moving said electrode (11; 11'), wherein said actuating device (26; 26') comprises a slider (26; 94) slidable along a sliding guide (27; 27') and arranged for being actuated by an operator so as to be moved along said sliding guide to progressively push said electrode through the hole so as to make the electrode (11; 11') progressively emerge from the cannula (10; 10') to an operative configuration, wherein the actuating device further comprises a cavity defined on the body at the sliding guide and designed to cooperate therewith to direct the sliding of the slider, said cavity comprising a first (29; 91) and a second sliding portion (30; 90) placed in succession and positioned side-by-side along the longitudinal axis of the body and defining two adjacent and successive sliding portions for the slider, wherein the actuating device further comprises a cavity defined on the body at the sliding guide and designed to cooperate therewith to direct the sliding of the slider, said cavity comprising a first (29; 91) and a second sliding portion (30; 90) placed in succession and positioned side-by-side along the longitudinal axis of the body and defining two adjacent and successive sliding portions for the slider, - said first portion (29; 91) being shaped so as to allow an axial translation of said slider (28; 94) along said guide (27; 27') to generate a consequent translation of said electrode in said cannula (10; 10'), and said second portion (30; 90) being configured so as to allow a rotational translation of said slider (28; 94) along said guide (27; 27') so as to generate a corresponding rotational translation of said electrode (11; 11') outside said cannula (10; 10').