{Problem} To prevent generation of mist and particulate, and prevent pressure fluctuations and reduced quality of the vacuum on the vacuum side can be prevented.
{Solution} A seal device employing magnetic fluid, characterized in being equipped with a magnetic fluid seal furnished in the axial center portion within a housing, and with rolling bearings furnished to both sides of the magnetic fluid seal;
a lubricated portion of the rolling bearing that, of the rolling bearings at either side, is the rolling bearing disposed on the vacuum side being filled with a magnetic fluid, and a magnet being installed on the vacuum side of an outer race; and
on the opposite side of the magnet from the outer race of the rolling bearing, a ring-shaped yoke made of magnetic material being installed in a loose-fitting manner onto the rotating shaft.