Each of claw-shaped magnetic poles is formed with an air gap expanding portion formed on at least a portion of both side portions in a circumferential direction, and an air gap is formed between the air gap expanding portion and tip portions of teeth that is larger than another air gap formed between radial end portions and the tip portions of the teeth. When a circumferential distance between the radial end portion and the tip portion is indicated by τ, and when the air gap is indicated by δ, 3δ≤τ≤15δ is satisfied. When a claw-tip end face width is indicated by L1, and when a claw-root end face width is indicated by L2, the claw-shaped magnetic pole is formed in a range of 0.20≤L1/L2≤0.71.