To provide a fixing device of a knuckle bracket, capable of preventing the knuckle bracket from loosening and producing backlash, even if external force such as vibration, load and the like is generated in the knuckle bracket and a shock absorber.

In this fixing device of a knuckle bracket 2, a cylinder part 3 of the knuckle bracket 2 is threadedly engaged with the periphery of an outer shell 1, and a nut 5 facing the cylinder part 3 is threadedly engaged with the periphery of the same outer shell 1. The feature of this fixing device is that a washer 9 having a V-shaped cross section and taper surfaces 7, 8 on the inner periphery is inserted to the peripheral side of the outer shell 1, taper locking surfaces corresponding to the taper surfaces are formed at the upper end of the cylinder part 3 and the lower end of the nut 5 respectively, and the upper end of the cylinder part 3 and the lower end of the nut 5 are fitted in the washer 9 while the locking surfaces 10, 11 are brought into pressure contact with the taper surfaces 7, 8 on the inner periphery respectively.