A fixing device, comprising: - a base member having a base surface; - a bracket member having at least one protruding portion protruding from the base surface of the base member and comprising a chamfer, the protruding portion having a first end adjacent the base surface of the base member and a second, opposite free end; - a mounting bending part to be attached to the free end of the protruding portion and having at least one elastic pre-fixing leg, and at least one fixing bending leg that is shorter than the pre-fixing elastic leg; and - a tightening member for tightening the mounting bending part along a tightening direction (d) against the bracket member to fix the mounting bending part to the protruding portion; whereby the mounting bending part and the protruding portion can be arranged so as to clamp to each other in at least one first relative position and a second relative position; wherein: - in the first relative position at least one portion of the fixing bending leg is arranged between the base surface of the base member and the chamfer of the protruding portion with at least one portion of the fixing bending leg contacting the chamfer; and - in the second relative position at least one portion of the pre-fixing elastic leg is arranged between the base surface of the base member and the chamfer of the protruding portion, and the fixing bending leg is arranged out of the first relative position; wherein the elastic pre-fixing leg has at least one first section and a second section, the first section extending away from the tightening direction (d) inclined at a first angle (α1), and the second section extending towards the tightening direction (d) inclined at a second angle (α2) different from the first angle (α1), and wherein the chamfer comprises an end portion onto which the fixing bending leg is allowed to slide to expand away from the tightening direction (d) as the tightening member is tightened against the bracket member. - a base member having a base surface; - a bracket member having at least one protruding portion protruding from the base surface of the base member and comprising a chamfer, the protruding portion having a first end adjacent the base surface of the base member and a second, opposite free end; - a mounting bending part to be attached to the free end of the protruding portion and having at least one elastic pre-fixing leg, and at least one fixing bending leg that is shorter than the pre-fixing elastic leg; and - a tightening member for tightening the mounting bending part along a tightening direction (d) against the bracket member to fix the mounting bending part to the protruding portion; whereby the mounting bending part and the protruding portion can be arranged so as to clamp to each other in at least one first relative position and a second relative position; wherein: - in the first relative position at least one portion of the fixing bending leg is arranged between the base surface of the base member and the chamfer of the protruding portion with at least one portion of the fixing bending leg contacting the chamfer; and - in the second relative position at least one portion of the pre-fixing elastic leg is arranged between the base surface of the base member and the chamfer of the protruding portion, and the fixing bending leg is arranged out of the first relative position; - in the first relative position at least one portion of the fixing bending leg is arranged between the base surface of the base member and the chamfer of the protruding portion with at least one portion of the fixing bending leg contacting the chamfer; and - in the second relative position at least one portion of the pre-fixing elastic leg is arranged between the base surface of the base member and the chamfer of the protruding portion, and the fixing bending leg is arranged out of the first relative position; wherein the elastic pre-fixing leg has at least one first section and a second section, the first section extending away from the tightening direction (d) inclined at a first angle (α1), and the second section extending towards the tightening direction (d) inclined at a second angle (α2) different from the first angle (α1), and wherein the chamfer comprises an end portion onto which the fixing bending leg is allowed to slide to expand away from the tightening direction (d) as the tightening member is tightened against the bracket member.