In the vibration isolating installation mechanism for a disposer of the present invention, a flexible cylinder with vibration isolatability and a suspension structure with vibration isolatability are used together, to support the disposer proper under an outlet-connected cylinder. The vibration isolating installation comprises an outlet-connected cylinder installed in the outlet of a sink by a clamp, to protrude downward, a disposer-installing cylinder for installing a disposer proper, a flexible cylinder connected between the outlet-connected cylinder and the disposer-installing cylinder, a support cylinder placed around the outlet-connected cylinder, support collars protruded horizontally respectively from the support cylinder and the disposer-installing cylinder, mating fitting holes formed in the support collars of both the cylinders at the respectively corresponding positions, support rods loosely fitted in the respectively mating fitting holes through an elastic bush respectively, and stoppers fitted at both the ends of each of the support rods.