To prevent the narrowing of a bearing clearance when the bearing load is high, and to prevent the hearing in relation to the same, by inserting a bearing into the bush having the higher expansion coefficient.

A material of a shaft 8 is steel, and a bearing on aerostatics, comprises the graphite bearings 6, 10, and the aluminum bushes 5, 9 forced onto the bearings 6, 10. The bushes 5, 9 pressed in excess, have the expansion coefficient at least three times as high as that of the ceramics bearing 6, 10, and that 1.3 times as high as that of the shaft material, and the indentation of high accuracy in size with the narrow manufacturing tolerance, can be stopped. The product is composed of elastic module and the wall thickness of the bush is at least 1.8 times as large as that of the bearing. The narrowing of the bearing clearance can not be found at the high bearing load, and the heating relating thereto, the friction of the bearing can be removed, and the balancing can be rapidly achieved when the heating is weakened again and the expansion is little.