A plurality of concavities and convexities is provided on tips of all rotor teeth 24 of the SR motor 5. Depths of the concave portions α are deep on an edge side where a stator tooth 23 and rotor tooth 24 first approach and are shallow as a facing area between the stator tooth 23 and rotor tooth 24 increases. Therefore, magnetic resistance between the stator tooth 23 and rotor tooth 24 becomes high at an early stage of the stator tooth 23 and rotor tooth 24 facing each other and becomes low as the facing area between the stator tooth 23 and rotor tooth 24 increases. As a result, torque fluctuation can be suppressed at a time of a large current and a minimum generation torque can be increased at a time of a small current.