A rolling bearing device includes: a bearing part having an inner ring, an outer ring, and balls; and an oil supply unit provided adjacent to an annular space between the inner ring and the outer ring and capable of supplying lubricating oil to the annular space. The bearing part has an annular cage provided in the annular space. The cage has a pair of annular parts and a plurality of bars. An outer circumferential surface of the annular part located on a first axial side has a contact portion capable of coming in contact with a part of an inner circumferential surface of the outer ring. A radially outer surface of the cage has, with the contact portion being a top, a first inclined surface provided from the top toward the first axial side and a second inclined surface provided from the top toward a second axial side.