PURPOSE: To realize a motor core which can reduce an iron loss, a cogging torque, an induced-voltage strain and a torque ripple and increase efficiency.

CONSTITUTION: A core for a motor is divided into laminated-core individual pieces 12 by split faces 14, and the laminated-core individual pieces 12 are constituted of unidirectional electromagnetic steel plates or bidirectional electromagnetic steel plates. A winding 15 is wound, via an insulating part 13, on every laminated-core individual piece 12, and the electromagnetic steel plates are laminated so as to decide an easy direction of magnetization at every laminated-core individual piece 12. A magnetic flux which is passed inside every laminated-core individual piece 12 flows to the easy direction of magnetization for the directional electromagnetic steel plates. In addition, a change in the direction of a magnetic flux flowing in a polar tooth or inside a gap at a rotation is reduced. An iron loss, an exciting current, an induced-voltage strain and a torque ripple can be reduced, so that the efficiency of the motor can be increased.