A 10-pole/9-slot synchronous motor includes nine teeth that are divided into three phases, each having three adjacent teeth. A stator iron core is configured such that a value obtained by dividing b by a is larger than 0.5 where the a is a width of a teeth tip, which is provided on an inner diameter side of a tooth of the teeth formed on the stator iron core, from a base portion between the teeth tip and the tooth to a circumferential end of the teeth tip and the b is a thickness of the teeth tip from the base portion to an inner-diameter side surface of the teeth tip.