Abstract: A rotary device comprises: a rotor; a plurality of magnetic poles distributed at angular intervals on the circumference of the rotor; a stator encircling the rotor; a plurality of magnetic poles disposed at angular intervals on the inner circumference of the stator; rotary magnetic shielding member disposed between the rotor and the stator so as to encircle the rotor and provided with magnetic paths distributed at angular intervals on the circumferential wall thereof encircling the rotor; and a synchronizing mechanism interlocking the rotor and the rotary magnetic shielding member so that the magnetic shielding member is rotated in synchronism with the rotor. The attractive force or the repulsive force acting between the magnetic poles of the rotor and the corresponding magnetic poles of the stator is varied by the magnetic shielding member so that the rotor is rotated continuously in one direction by the attractive force or the repulsive force.