Three-row roller slewing bearing has three seat-rings, which separate the upper, lower and radial races, via which the load of each row of the rollers may be specified. It may bear different loads simultaneously and its load capacity is the largest one among the four models. Thanks to the large size of its axle and radius, it is sturdy and especially suitable for heavy-duty machines which require large working radius. such as bucket-wheel excavators, wheeled cranes, ship cranes, ladle turret, heavy duty mobile cranes etc.