A cushioned mounting device for use in mounting an engine to the body of a vehicle such as an automobile, having first and second frame members arranged to oppose to each other, a mass member having a plate portion and disposed between the first and the second frame members, a first cushion member disposed between and flexibly connecting together the first frame member and the mass member, and a second cushion member disposed between and flexibly connecting together the second frame member and the mass member, wherein the mass member, together with the first and the second cushion members, forms a sub-oscillation system which can provide less than one transmission ratio relative to an oscillation system supposed to be composed of the engine supported by this cushioned mounting device and the first and the second cushion members which can also provide less than one transmission ratio, whereby the cushioned mounted device cna provide a low overall transmission ratio which is substantially the multiplication of the above two less than one transmission ratio.