PURPOSE: To exhibit a required high speed performance with a high economic benefit, by using a motion fluid suitable for a high speed operation and that not suitable for the high speed operation with their changing over as occasion demands.

CONSTITUTION: A pair of static pressure rooms 3, 4 located independently each other at both right and left sides of a guide 1 are formed between the guide 1 and a moving stage 2, and fluid feeding pipelines 7, 8 having valves 5, 6 independent respectively are connected to the static pressure rooms 3, 4. An air source 11 and a helium source 12 are then connected via a changeover valve 13 to this fluid feeding pipelines 7, 8, a static pressure bearing is composed with a static pressure being caused in the static pressure rooms 3, 4 in case of the fluid being fed to the static pressure rooms 3, 4 from which thereof, the moving stage is floated to the guide 1 to enable a high speed movement. Now, a helium source 12 is selected in case of a speed property being necessary, the air source 11 is selected in case of the speed property being not requested.