In a bearing according to an embodiment, a pair of magnets is arranged such that sides of the magnets opposed to each other with rolling members interposed therebetween have different magnetic polarities from each other. A magnetic fluid sealed bearing according to another embodiment includes a nonmagnetic spacer disposed between a magnet of one of magnetic fluid seals and a magnet of the other of the magnetic fluid seals so as to form a magnetic circuit that penetrates outer and inner rings and goes around the rolling members.