PROBLEM TO BE SOLVED: To provide an air turbine rolling bearing which can make compatible both high-speed rotation and its quick stop, and an air turbine bearing unit.SOLUTION: A rolling bearing 1 comprises: an outer ring 10； an inner ring 20； a plurality of rolling bodies 3； and a substantially-annular member 30 which is arranged at one end part of a bearing internal space S between the outer ring 10 and the inner ring 20 in an axial direction, and composed of an elastic body having no core grid. An external peripheral part of the substantially-annular member 30 is fixed to a groove part 13 formed at an internal peripheral face of the outer ring 10 at one end part in the axial direction by a snap ring 40, and an internal peripheral part is made elastically changeable. An external peripheral face 21 of the inner ring 20 has an inclined face 23 or a step part which becomes small in a diameter toward an axial end. One end part in the axial direction for installing the substantially-annular member 30 is located at a side opposite to an inlet of compressed air which is supplied to the bearing internal space S.SELECTED DRAWING: Figure 2【課題】超高速回転とその迅速な停止とを両立可能なエアタービン用転がり軸受及びエアタービン軸受ユニットを提供する。【解決手段】転がり軸受１は、外輪１０と、内輪２０と、複数の転動体３と、外輪１０と内輪２０との間の軸受内部空間Ｓの軸方向一端部に設けられ、芯金が無い弾性体からなる略環状部材３０とを備える。略環状部材３０は、外輪１０の軸方向一端部の内周面に形成された溝部１３に外周部が止め輪４０によって固定されて、内周部が弾性変更可能にされている。内輪２０の外周面２１は、軸端に向かって大径から小径となる傾斜面２３又は段差を有する。略環状部材３０を設ける上記軸方向一端部は、軸受内部空間Ｓに供給される圧縮空気の入口とは反対側である。【選択図】図２
