A manufacturing method of a motor core includes laminating in an axial direction steel plates extending in a radial direction with respect to a central axis, each of the laminate steel plates including a base portion on a radially outer side of the central axis, annular portions separately disposed on a radially outer side of the base portion with penetrating portions therebetween, and connecting portions at predetermined intervals in a circumferential direction to extend in the radial direction and connect the base portion and the annular portions, the annular portions including coupling portions adjacent to both circumferential sides of the connecting portions, and cutting at least one of the two coupling portions adjacent to one connecting portion in the circumferential direction from an outer side to an inner side of the laminate steel plates in the radial direction with respect to the laminate steel plates that are laminated.