An apparatus for manufacturing a stator. On a split core of the stator, there are wound main conductors and two auxiliary conductors, which are thinner than but correspond to the main conductors. These main conductors are arrayed and wound in a plurality of layers, such that the main conductors of an upper layer are arranged in the valleys between the adjoining main conductors of a layer. For the main conductors of a first layer, the auxiliary conductors are arranged in a first space and a second space. For the main conductors of the second and subsequent layers, the auxiliary conductors are arranged in a third space, and the auxiliary conductors are arranged in a fourth space.