A stator is provided with a tooth, an insulator attached to the tooth, and a coil wound around the insulator. The insulator is provided with a winding barrel around which the coil is wound in a plurality of layers, a flange projecting in a radial direction from one end of the winding barrel, and a notch formed in the flange and through which the line material of the coil is inserted. Projecting lengths of the flange from the winding barrel on the both sides of the notch are set different from each other. When the line material of the coil is guided from the outside of the flange to the winding barrel through the notch for winding the coil on the winding barrel, by supporting and bending the line material at a portion having a longer projecting length of the flange, the line material passes the notch easily.