To provide a swing bearing fixing structure to a revolving super structure of a crawler crane, including a boom, a base carrier, a revolving super structure, and a swing bearing and being the optimum for preventing an increase in weight and vehicle width of a crane body and reducing shaft force of a bolt.

This swing bearing fixing structure includes a pair of side plates 2, 2 extended and erected on the right and left sides in the longitudinal direction of a bottom plate 1 constituting the revolving super structure and a bolt shaft force reducing means 8a composed of a bottom plate protruding part 1a and a first additional fixing bolt 4a to reduce the bolt shaft force of a bearing fixing bolt 4c in at least part of this fixing structure. The swing bearing 3 is fixed on the bottom plate 1 constituting the revolving super structure by the bolt shaft force reducing means 8a and the bearing fixing bolt 4c arranged on the bottom plate 1 along a fixing position of the swing bearing 3.