A spindle device comprising: a rotating shaft which has a plurality of turbine blades installed in a circumferential direction and is configured to mount a mounting object on a tip; a housing which accommodates the rotating shaft; a radial bearing which is attached to the housing and floatingly supports the rotating shaft in a non-contact manner with respect to the housing by supplying gas; a thrust bearing which is attached to the housing and supports the rotating shaft in a thrust direction with respect to the housing by supplying gas; a case which is arranged to surround an outer peripheral surface of the housing; and a plurality of O-rings (61, 62, 63, 64) which are arranged between the housing and the case and support the housing with respect to the case, wherein: the spindle device rotationally drives the rotating shaft by ejecting gas to the plurality of turbine blades; at least one O-ring is arranged between a center of the radial bearing and the center of gravity of the rotating shaft in an axial direction of the rotating shaft; characterized in that a distance from a rear end surface of the thrust bearing to a center of gravity of the rotating shaft is larger than a diameter of an area center of the thrust bearing; and that two O-rings (63, 64) are arranged on the rear end side of the housing from the center of the radial bearing. a rotating shaft which has a plurality of turbine blades installed in a circumferential direction and is configured to mount a mounting object on a tip; a housing which accommodates the rotating shaft; a radial bearing which is attached to the housing and floatingly supports the rotating shaft in a non-contact manner with respect to the housing by supplying gas; a thrust bearing which is attached to the housing and supports the rotating shaft in a thrust direction with respect to the housing by supplying gas; a case which is arranged to surround an outer peripheral surface of the housing; and a plurality of O-rings (61, 62, 63, 64) which are arranged between the housing and the case and support the housing with respect to the case, wherein: the spindle device rotationally drives the rotating shaft by ejecting gas to the plurality of turbine blades; at least one O-ring is arranged between a center of the radial bearing and the center of gravity of the rotating shaft in an axial direction of the rotating shaft; characterized in that a distance from a rear end surface of the thrust bearing to a center of gravity of the rotating shaft is larger than a diameter of an area center of the thrust bearing; and that two O-rings (63, 64) are arranged on the rear end side of the housing from the center of the radial bearing. the spindle device rotationally drives the rotating shaft by ejecting gas to the plurality of turbine blades; at least one O-ring is arranged between a center of the radial bearing and the center of gravity of the rotating shaft in an axial direction of the rotating shaft; characterized in that a distance from a rear end surface of the thrust bearing to a center of gravity of the rotating shaft is larger than a diameter of an area center of the thrust bearing; and that two O-rings (63, 64) are arranged on the rear end side of the housing from the center of the radial bearing.