Protrusions 540 are provided on an outer circumferential surface of an outer circumferential wall 533 of an insulator 530. Two lead wires 521 out of three lead wires 521 of coils 520 are drawn out to an outer circumferential side of the outer circumferential wall 533 and are hooked on the protrusions 540. Thus, sway of the lead wires can be prevented without increase in number of components and troubles with work.