Patent ID: 7211908

Claim:
A magnetic floating device for floating a movable portion relative to a fixed portion, on the basis of a magnetic force, comprising: a plurality of first permanent magnets provided on one of the movable portion and the fixed portion; and a second permanent magnet provided on the other of the movable portion and the fixed portion, said second magnet being disposed to be sandwiched by the first magnets in the manner that the same magnetic poles are opposed to each other; wherein the movable portion and the fixed portion are held relatively movably in a floating direction and in an intersecting direction that intersects with the floating direction and a polarizing direction of the first magnet, and wherein the second magnet is disposed within a range of an extreme value position of a distribution, in the intersecting direction, of a magnetic flux density produced between the first magnets by the first magnets, at an opposing surface of the second magnet being opposed to the first magnet, and when Lsx is the size of each of the first magnets in an intersecting direction that intersects with a floating direction and the polarization direction of each of the first magnets, Lsy is the size of each of the first magnets in the polarization direction, Lrx is the size of the second magnet in the intersecting direction, Lry is the size thereof in the polarization direction, and Gd is the spacing between the first magnets, a relation Lsx/ 2 <Lrx<Lsx −( Lsy−Gd−Lry ) is satisfied.