In a housing that supports a rotating shaft via a rolling bearing which is subjected to predetermined position precompression, a wedge member, the radial thickness of which increases from the leading end towards the base end thereof, is inserted between the housing and the outer circumferential surface of the outer race of the rolling bearing and between the rotating shaft and the inner circumferential surface of an inner race of the rolling bearing, the wedge member being inserted from the leading end thereof along the radial direction of the rotating shaft. The wedge member is fixed by being fastened, ahead in the insertion direction, by bolts and nuts, so that precompression force along with predetermined position precompression is imparted to the rolling bearing.