A positioning apparatus of an exposure apparatus includes a chamber, a substituting
unit for substituting a gas in the chamber from a first gas to a second gas, a
static pressure gas bearing provided in the chamber, a gas supply unit for supplying
the second gas to the static pressure gas bearing, a control unit for controlling
the gas supply unit to supply the second gas to the static pressure gas bearing
when the substituting unit substitutes the gas in the chamber from the first gas
to the second gas, and a bearing exhaust unit for exhausting the gas of the static
pressure gas bearing.