A rolling bearing system for supporting a shaft member rotatably in a housing, said rolling bearing system comprising: a housing; a shaft member; an outer ring; an inner ring which is fixed to the shaft member; a ring member; and a plurality of rolling elements that roll while in contact with the outer ring and the inner ring in a radial direction, the outer ring comprising a single piece which includes: an annular section whose inner surface has a rolling motion surface on which the rolling elements roll; and a projecting section that projects radially outwardly while being connected in an integrated manner with an axial end of the annular section; the ring member being provided radially outside of an outer surface of the annular section, the ring member covering the outer surface around an entire circumference of the outer surface, the ring member and the outer surface partitioning an annular space (G, R40) therebetween, the rolling elements being pressed against the outer ring and the inner ring by pressurized fluid supplied to the annular space (G, R40), characterized in that the projecting section is fixed to the housing so that a radial load, which acts on the shaft member, is transmitted to the housing via the projecting section, and that the rolling elements are pressed radially against the outer ring and the inner ring by diameter reduction of the annular section due to elastic deformation of the annular section in the radial direction, which elastic deformation is caused by pressure of said pressurized fluid on said outer surface of the annular section. a housing; a shaft member; an outer ring; an inner ring which is fixed to the shaft member; a ring member; and a plurality of rolling elements that roll while in contact with the outer ring and the inner ring in a radial direction, the outer ring comprising a single piece which includes: an annular section whose inner surface has a rolling motion surface on which the rolling elements roll; and a projecting section that projects radially outwardly while being connected in an integrated manner with an axial end of the annular section; the ring member being provided radially outside of an outer surface of the annular section, the ring member covering the outer surface around an entire circumference of the outer surface, the ring member and the outer surface partitioning an annular space (G, R40) therebetween, the rolling elements being pressed against the outer ring and the inner ring by pressurized fluid supplied to the annular space (G, R40), characterized in that the projecting section is fixed to the housing so that a radial load, which acts on the shaft member, is transmitted to the housing via the projecting section, and that the rolling elements are pressed radially against the outer ring and the inner ring by diameter reduction of the annular section due to elastic deformation of the annular section in the radial direction, which elastic deformation is caused by pressure of said pressurized fluid on said outer surface of the annular section. the outer ring comprising a single piece which includes: an annular section whose inner surface has a rolling motion surface on which the rolling elements roll; and a projecting section that projects radially outwardly while being connected in an integrated manner with an axial end of the annular section; an annular section whose inner surface has a rolling motion surface on which the rolling elements roll; and a projecting section that projects radially outwardly while being connected in an integrated manner with an axial end of the annular section; the ring member being provided radially outside of an outer surface of the annular section, the ring member covering the outer surface around an entire circumference of the outer surface, the ring member and the outer surface partitioning an annular space (G, R40) therebetween, the rolling elements being pressed against the outer ring and the inner ring by pressurized fluid supplied to the annular space (G, R40),