PURPOSE: To make the extent of maintainability improvable, by letting a swivel stage form each bearing surface in four sides of a square cylinder, and making X-axis and Y-axis movable guides set up a pair of straight guide members parallelly in accord with the square cylinder.

CONSTITUTION: In and around a surface plate 1 forming a flat sliding surface 11 on the top, there are provided with X-axis guides 12, 12a and Y-axis guides 13, 13a being paralleled with each other. An X-axis movable guide 2 and a Y-axis movable guide 3 are reciprocatably supported between these opposed guides, and a swivel state 4 is set up, through a bearing, in a cross part of these X and Y movable guides 2 and 3. In this swivel stage, flat bearing surfaces 42 and 43 are formed in both length and breadth sides of a square cylinder 41 consisting of a bearing material. It is made of directly supporting each of these bearing surfaces 42 and 42 on bearing guide ways 23 and 33 of straight guide members 21 and 31 forming these X-and Y-axis movable guides 2 and 3. In the square cylinder 41 forming the swivel stage 4, there is provided with a built-in wafer driving mechanism inside.