A fixing mechanism includes a shaft, a constraining member, a sleeve member, a resilient bushing, a pivot member and a handle. The constraining member is connected to an end portion of the shaft. The sleeve member sheathes the shaft. The resilient bushing sheathes the shaft and is disposed between the constraining member and the sleeve member. The pivot member is connected to the other end portion of the shaft. The handle is pivoted to the pivot member and abuts against the sleeve member. The handle pushes the sleeve member and drives the pivot member to activate the shaft to pull the constraining member when the handle pivots relative to the pivot member, so that the constraining member and the sleeve member cooperatively compress the resilient bushing, so as to make the resilient bushing generate a radial deformation.