The present invention provides a stage apparatus wherein an object is disposed in an atmosphere with a gas pressure lower than atmospheric pressure, and the object can be driven with high accuracy. The stage apparatus that drives a reticle comprises: a vacuum chamber, which forms a space and has an opening; an integrated coarse and fine motion table, which has an electrostatic chuck that holds the object, that, when driven, moves the electrostatic chuck inside the space; a counter mass, which is disposed so that it covers the opening, that is capable of moving because of the reaction force produced when the integrated coarse and fine motion table is driven; and a vacuum cover, which forms a space that houses the counter mass; wherein the space and the space are set to prescribed gas pressures.