To provide a multi-link rear suspension device having an efficient structure able to increase the space of a trunk, and at the same time, decrease noises in the cabin and enhance the comfortableness.

The multi-link rear suspension device is composed of a knuckle installed in a space inside each rear wheel, a rear sub-frame whose two ends are coupled with the vehicle body in the condition arranged in the vehicle width direction for increasing the rigidity of the body under-part, an upper arm coupled with the top of the knuckle and the rear sub-frame, a lower arm coupled with the bottom of the knuckle and the rear sub-frame, an assist arm installed on the front side of the vehicle body using the rear sub-frame as reference and coupled with the knuckle and the rear sub-frame, a trailing arm coupled with the knuckle and the body side, a coil spring, and a shock absorber.