To easily form an inverted wave winding coil with a continuous line without changing a folding method.SOLUTION: A manufacturing method of a wave winding coil, includes: an inversion form forming step of having a plurality of slots arrangement parts 11 formed by a continuous line 10, and arranged in a slot 23 of a stator core 20, and a turn part 12 connecting both of the adjacent slot arrangement parts 11, having a U-character part 12A, and a liner part 14 in a continuous line 10, and forming an inversion form arranged inside of the U-character part 12A of the other one continuous line 10 by the U-character part 12A of the one continuous line 10 from at least the two continuous lines 10 belonged to the same phase; an oblique part formation step of forming an oblique part 15 to each continuous line 10 by off-setting a pair of liner parts 14 of each continuous line 10 on which the inversion form is formed; and a folding step of folding each continuous line 10 on which the oblique part 15 is formed, and forming the turn part 12 and each slot arrangement part 11. The oblique part formation step and the folding step are alternately performed.SELECTED DRAWING: Figure 8