A step of inserting an insulating paper into a slot of a stator core (second step) is performed, a step of placing a jig at a position that is on a side opposite to a side from which a segment coil is inserted into the slot of the stator core and that overlaps with a protrusion when viewed in an inserting direction of the segment coil (third step) is performed, and then a step of inserting the segment coil into the slot (fourth step) is performed. Therefore, even when the insulating paper is dragged by the segment coil in the process of inserting the segment coil into the slot, the insulating paper abuts the jig and the movement of the insulating paper is restricted, thereby suppressing displacement of the insulating paper from the slot.