There is provided a compact stator coil assembly that has heat radiation increased and a cooling performance improved. A stator coil assembly includes a first coil piece, a second coil piece, and an insulating member provided with a retaining portion that catches the first coil piece and the second coil piece so that those coil pieces form a predetermined coil pattern. A coil loop is formed by the first coil piece and the second coil piece. The stator coil assembly further includes a heat-transfer member having a heat-transfer portion insulated from the first coil piece and the second coil piece and embedded in the insulating member, and a slit formed in the heat-transfer member so as to cut off the pathway of an induced current that is to flow through the heat-transfer member.