Insulators are respectively disposed such that longitudinal directions of trunk portions are oriented in a radial direction of teeth, and so as to place bottom surfaces of the trunk portions alongside two axial end surfaces of the teeth, concentrated winding coils are configured by winding conductor wires so as to be wound in multiple layers around the teeth so as to pass through a concave space that is formed by the trunk portions and first and second flange portions at two axial ends of the teeth, the second flange portion is disposed on an end surface of a core back of a stator core, and a temperature detecting element is installed by being inserted into an element insertion aperture that is formed on the second flange portion so as to be able to detect a temperature of a coil end of the concentrated winding coils.