Sub core sections are arranged at the end portions and the center portion of a stator core, and strand conductors are twisted and transposed by 360 degrees continuously toward the extending direction of winding slot. The length corresponding to transposition pitch 180 degrees of the strand conductors of the stator core is set as one core unit area, the sub core sections including portions whose space factors are different are arranged such that the sum of voltages in the strands induced in the strand conductors in the odd-numbered core unit area from one end portion of the stator core offsets the sum of voltages in the strands induced in the strand conductors in the even-numbered core unit area from the end portion of the core.