A stator includes a stator core having slots and a stator coil comprised of three star-connected phase windings. In each of the slots, there are arranged in-slot portions of the phase windings in six layers. Each of the phase windings is comprised of five parallel-connected sub-windings. At each of the six layers, the in-slot portions of the sub-windings are arranged in a plurality of slot pairs; the slot pairs are circumferentially spaced from one another and each consist of two consecutive slots that are respectively identified as types A and B of the slots. Moreover, for each of the sub-windings, the in-slot portions of the sub-winding are evenly distributed to the two types A and B so that the number of the in-slot portions of the sub-winding arranged in the slots of the same type at each of the six layers is equal to 2.