To reduce the number of components and to facilitate coil winding work.

A coil bobbin 10 is configured by integrally including coil winding parts 101 and 102 for winding coils 21 and 22. Yokes 41 and 42 are mounted on the coil winding part 101, and yokes 43 and 44 are mounted on the coil winding part 102. When forward and reverse energizing is executed to the coils 21 and 22, rotor members 51 and 52 are turned back and forth. In the coil winding part 101, an area surrounded by a first virtual plane F1a vertical to the direction of an axis A including one end 101a in the windable range of the coil 21 in the direction of the axis A and a second virtual plane F1b vertical to the direction of the axis A including the other end 101b does not interfere with parts other than the coil winding part 101 in the coil bobbin 10. It is similar for the coil winding part 102 as well.