A first and a second static-pressure gas bearings supporting a rod at two locations in the axial direction in the non-contact manner are provided, in which the first static-pressure gas bearing is fixedly supported by a bearing housing, while the second static-pressure gas bearing is supported capable of displacement through a movable support mechanism. And this movable support mechanism has an actuator and suppresses contact of the rod with the static-pressure gas bearings by displacing the shaft center of the second static-pressure gas bearing with respect to the first static-pressure gas bearing by this actuator according to a load acting on the rod.