A base member includes a base groove portion, a base through-hole, and an insulating sheet portion. The base groove portion is positioned on a lower surface of the base member. The base through-hole extends through the base member. The first insulating sheet portion is arranged on a bottom surface of the base groove portion. A lead wire extended from a coil is led out into the base groove portion through the base through-hole and is connected to a land portion. The base through-hole has a diameter which is different depending on the direction in which it extends. The base through-hole includes a major and minor axis extending in a direction where the diameter is largest and smallest respectively. A portion of an edge of the first insulating sheet portion on the lower surface of the base member intersects the major axis and covers a portion of the base through-hole.