PURPOSE: To provide a double vibration preventing function to prevent effectively the occurrence of confined sound in a compartment, by supporting a differential carrier through an insulator with a suspension device on both front and rear ends.

CONSTITUTION: In the case of a rear suspension system 1a of a FR car, when a differential carrier 4 is supported on both ends through insulators 6, 6a by a suspension member 3 mounted on a car body, mounting plates 30, 30a projecting widthwise of the car are fixed to the front end of said carrier 4 by bolts 31. And the mounting plates 30, 30a are fixed to said member 3 through first insulators 32, 32a by bolts 33. Also, the carrier 4 is formed on the rear end with a projection 34 and supported by a bracket 7 attached fixedly to the member 3 by a frame 36 and the like through a second annular insulator 35 fitted onto the outer periphery of the projection 34.