To provide a magnetic bearing unit well controllable and suppressible of energy consumption as much as possible by utilizing a permanent magnet efficiently.

Under the condition of the bearing gaps S1 and S2 arranged between a rotator 1 and a bearing, the magnetic bearing unit is provided with magnetic cores 10 and 40 using plate- or ring-shape permanent magnets 20 and 50, a rotator 1 is lifted up by magnetic force, and the thicknesses t2 and t1 of the permanent magnets 20 and 50 are not less than the bearing gaps S2 and S1 but not greater than 4 times of them.