To easily remove dust on a surface plate by a simple structure in which, when a foreign substance is present on a counter face, the foreign substance is guided by a guide unit together with fluid ejected from a bearing face in a direction separated from the counter face.

A base pad 100 as a fluid hydrostatic bearing is attached to a lower face of a base 41a of a weight canceling device 40 where pressurized air ejected from a bearing face 106a to a surface plate 12 flows along an inclined face 107 which is continuously formed on the bearing face 106a by a Coanda effect. On this occasion, dust D on the surface plate 12 is attracted to the pressurized gas by a Bernoulli effect and guided together with the pressurized gas in a direction separated from the surface plate 12. The pressurized gas is filtered by a filter member 126 and discharged outward from the base pad 100. Since the base pad 100 can suck dust D on the surface plate 12 without using a special suction device, the base pad has a simple structure.