Dust core and method of manufacturing the same

A method of manufacturing a dust core, comprising the steps of:

• forming a plurality of arcuate dust core pieces each integrally having a yoke extending in an arc shape and a tooth projecting in a radial direction of said yoke, by performing pressure forming on soft magnetic powder;
• fabricating each of first and second annular dust core pieces by disposing each of said plurality of arcuate dust core pieces along a circumferential direction of said yoke and joining said plurality of arcuate dust core pieces;
• forming an additional annular dust core piece having the same planar shape as that of the first and second annual dust core pieces, wherein said additional annular dust core piece has a straight cross section in the yoke and the tooth;
• and
• stacking said plurality of arcuate dust core pieces in a height direction and joining said plurality of arcuate dust core pieces, wherein said additional annular dust core piece is interposed between the first and second annular dust core pieces.