PURPOSE: To enable a mobile body to be used at a surface which is not horizontal and to achieve improved accuracy by guiding the mobile body on one surface of base and by providing guide rigidity in a direction which crosses the base at right angle by a magnet and fluid bearing.

CONSTITUTION: Bearing pads 41 are provided in the upper and lower parts of the surface opposite to a vertical slider 29 to constitute a plane fluid bearing. Also, a magnet 42 is provided between these bearing pads 41 and a bearing pad 43 is provided at the surface facing the side surface of a guide main unit 25 of the vertical slider 29. Then, if fluid is discharged from the bearing pad 41, the vertical slider 29 is lifted from a base 21 by static pressure floating force and the point where this static floating force and magnetic absorption force by a magnet 42 are balanced corresponds to the floating gap. In the static pressure bearing, after the pressure of pressure-applied fluid is reduced to an intermediate pressure by a throttle, it is discharged at the floating gap. And the pressure is further reduced within the gap and the fluid is released into atmospheric pressure. If an external force acts upon a bearing changing the gap, the intermediate pressure changes, operating to prevent the gap from changing, thus giving rigidity to the bearing.