Abstract: The stator includes core back iron cores disposed on outer circumferential sides between a plurality of teeth iron cores disposed at regular intervals of a predetermined distance in a predetermined circumferential direction. A stator winding is disposed on inner circumferential sides between the plurality of teeth iron cores. The stator winding is constituted by a plurality of wire bundles each of which is a bundle of a predetermined number of electric wires and which are connected in parallel with one another. The wire bundles are set so that the number of electric wires constituting a wire bundle located on the inner circumferential side between adjacent teeth iron cores is smaller than the number of electric wires constituting a wire bundle located on the outer circumferential side. Hence, the ratio (L/A) of the circumferential length L of each wire bundle to the sectional area A thereof is set at a value in a predetermined allowable range.