In the embodiment described above, the plurality of lead wires led out from the wire leading-out holes were arranged so as to be lined up in a row; therefore, the shape of the horizontal cross-section of the wire covers was configured so as to be elongated in a direction along which the led out lead wires are lined up. However, the contour shape of the horizontal cross-section of the wire covers may be configured so as to be round, regularly polygonal, or another suitable shape. In cases where the contour shape of the horizontal cross-section of the wire covers is configured so as to be round or regularly polygonal, it is possible to impart three-fold or higher rotational symmetry to the contour shape of the horizontal cross-section of the wire covers.

In the embodiment described above, a case where there was used a motor housing 2 of a type in which the end member 201 that closed the one axial end of the cylindrical part 200 was provided integrally with the cylindrical part 200, and in which the end member 202 that closed the other axial end of the cylindrical part 200 was provided separately from the cylindrical part 200, was used as an example. However, the present invention can also be applied to cases where a motor housing of a type in which the cylindrical part 200 is divided into two housing halves midway along the axial direction, a motor housing in which both the end member 201 that closes the one axial-end side of the cylindrical part 200 and the end member 202 that closes the other axial-end side of the cylindrical part 200 are provided separately from the cylindrical part 200, or another type of motor housing is used.