To cool the lead wire of the coil of a rotary electric machine efficiently in simple structure.

The coil 11 of a rotary electric machine is constituted by winding a flat wire 14 in piles into two or more layers at the winding sections 15a and 16a of an insulator 13 covering the periphery of an iron core 12. The space 19 made between the winding sections 15a and 16a of the insulator 13 and the flat wire 14 is charged with varnish 20 through a path made between the grooves 15e, 15f, and 15g of the insulator 13 and the iron core 12. The heat of the rectangular wire 14 is conducted to the iron core 12 via the varnish 20 and the insulator 13, whereby the flat wire 14 can be cooled by making it perform the heat radiation effectively. Besides it can contribute to the cost down since a refrigerant, a pump for circulating it, and others become needless.