To provide a rear wheel suspension unit of a vehicle, which reduces spaces occupied by springs and shock absorber assemblies to utilize the inner space of the vehicle efficiently and suppresses vibrations.

The rear wheel suspension unit comprises carriers 19, a plurality of arms, which include lateral lower arms 2 connecting the carriers 19 to subframes 22, lateral auxiliary arms 9, lateral upper arms 6, and vertical arms 15, the springs 5, and the shock absorbers 12. The lateral upper arms 6 are arranged in front of the lateral lower arms 2, the springs 5 are anchored to the lateral lower arms 2, the lower end fixed parts of the shock absorbers 12 are connected to the carriers 19 in a position lower than the connection between the carriers 19 and the lateral lower arms 2, and the upper end fixed parts of the shock absorbers 12 are connected to the side face of the frame of the vehicle.