To realize displacing of a proportional rotary torquer to an arbitrary rotary angle position in response to the amplitude and the energizing direction of an exciting current with a simple structure.
Salient poles 3a, 3b formed in a rotor core 3 are formed drawing a circular arc having a diameter at its central part different from the diameter at a boundary part on the opposed surfaces to permanent magnets 1a, 1b. An angle K between the connecting lines of a boundary end point of both the ends of the salient poles 3a, 3b and a rotating center is formed to become about 100° or more. The permanent magnets 1a, 1b are formed of circular arc surfaces having different central positions so that the thickness B of the pole boundary part becomes about 90-95% of the thickness A of the central part of the poles.