A electrically insulating member, which covers a stator core, has a plurality of engagement claws, which extend in the axial direction of a rotary shaft, and a plurality of positioning projections, at positions in the circumferential direction differing from those of the engagement claws, which extend further than the engagement claws. A sensor board, on which a plurality of magnetic sensors are fixed in place, has engagement parts, which engage with the engagement claws, and positioning recesses, into which the positioning projections are inserted.