The continuous wires respectively have U-shaped parts and straight parts. The method includes: a transposition shape forming step of forming transposition shapes in each of which, among at least the two continuous wires belonging to an identical phase, the U-shaped part of one of the continuous wires is disposed inside the U-shaped part of the other one of the continuous wires; an inclined part forming step of causing the pairs of straight parts of the continuous wires respectively formed with the transposition shapes to be offset to form inclined parts on the continuous wires; and a folding step of folding the continuous wires formed with the inclined parts to form the turning parts and the slot disposition parts. The inclined part forming step and the folding step are alternately performed.