A stator coil 24 is installed in a stator core 11, and an insulating resin is impregnated into slot portions 22 and hardened. The stator coil 24 is constituted by enameled wires in which a polyamideimide resin layer has been applied radially outside a copper wire and hardened, and the insulating resin contains as a major component a THEIC-modified polyester resin that has been modified by a fatty acid.