Winding bodies are produced by repeatedly winding a δ-shaped coil pattern that is formed by inserting the conductor wire sequentially into a second slot, a first slot, a second slot, and a third slot, so as to alternate an axial direction of insertion into the first slot, the second slot, and the third slot, for two turns in a radial direction, and are configured such that a plurality of rectilinear portions that are respectively inserted into the first slot, the second slot, and the third slot are linked continuously by coil end portions, and a liquid coolant is supplied to a coil end that is constituted by the coil end portions.