To provide a double-row tapered roller bearing capable of avoiding interference between an inner ring spacer and a small diameter side side-plate while maintaining the rigidity of the inner ring spacer to a certain value and a spindle supporting structure of an aerogenerator.
A relief part 20 reduced in thickness is formed in the inner ring spacer 18 in an area facing the minimum inner diameter portions of the small diameter side side-plates 17a and 17b during assembly. The relief part 20 is formed in such a stepped shape that its thickness is reduced from the outer diameter part 19 of the inner ring spacer 18 to a diameter at which the small diameter side side-plates 17a and 17b are not interfered with each other, namely, the center part of the inner ring spacer 18 is formed thick and both end parts thereof are formed thin.
Morishita Hachiro
Hiroyuki Yoshida