Positional information of wafer stages is measured by a plurality of encoder heads, Z heads and the like that a measurement bar placed below surface has, using gratings placed on the lower surface of fine movement stages. Consequently, high-precision measurement of the positional information of the wafer stages can be performed. Further, since a guide surface of the wafer stages is formed by the two guide surface forming members placed side by side via a predetermined clearance, each guide surface forming member is easier to handle and also maintenance of the vicinity of the guide surface forming member is easier to perform, compared with the case where the guide surface forming members are integrated.