To make it possible to easily assemble and prevent rattling.

Positioning portions 15 and 16 are respectively formed at both side faces orthogonal to the peripheral direction of a rotor of a stator magnet holding hole 9. The positioning portion 15 is equipped with two magnetic supporting portions 34 and 35 arranged in parallel to the direction of the axis of rotation. The magnet supporting portion 34 is formed by connecting a pair of supporting portions 21 and 22 formed as if extending from the base portion 20 to peripheral direction, an escape portion 24 formed between both supporting portions 21 and 22, and between the tip portions of both supporting portions 21 and 22, and is constituted with a deforming plate portion 26 which deforms in the escape portion 24 by an energizing force from the side of the stator magnet holding hole 9 and a projected strip 28 coming into contact with the side face of a stator magnet 10.