In the present embodiment, the positioning members 143 are made of material identical to that of the magnetic pieces 141 and integrally formed with the magnetic pieces 141. As the material of the magnetic pieces 141 and the positioning members 143, soft magnetic metal powder bound by binder can be used. However, the present invention is not limited thereto. The positioning members 143 may be made of material different from that of the magnetic pieces 141. Moreover, the number and an arrangement of the positioning members 143 may be decided according to material to be used and the like.

FIGS. 4 and 5 show another magnetic member 14A which can be used in the circuit board 10 instead of the magnetic member 14. The magnetic member 14A is provided with a plurality of magnetic pieces 141 and a positioning member 143 which is made of a single insulating resin sheet. The positioning member 143A couples one surfaces of the magnetic pieces 141 with one another. In detail, the positioning member 143A couple lower surfaces of the magnetic pieces 141 with one another. In each of the lateral direction and the front-rear direction, a size of the positioning member 143A is larger than that of an area on which the magnetic pieces 141 are arranged. However, the present invention is not limited thereto. In at least one of the lateral direction and the front-rear direction, the size of the positioning member 143A may be equal to or smaller than that of the area on which the magnetic pieces 141 are arranged. But the positioning member 143A should couple the magnetic pieces 141 with one another.