Provided is a 10-pole/9-slot synchronous motor comprising nine teeth (2b) that are divided into three adjacent phases. The stator core (2) is formed so that when the width of a tooth tip section (2c) that is provided to the inner diameter side of a tooth (2b) that is formed on a stator core (2) from a joint section (2b1) of the tooth tip section (2c) and the tooth (2b) to a circumferential-direction end section (2c1) of the tooth tip section (2c) is denoted by a and the thickness of the tooth tip section (2c) from the joint section (2b1) to the inner diameter-side surface (2c2) of the tooth tip section (2c) is denoted by b, the value obtained by dividing b by a is larger than 0.5.
