A motor manufacturing method includes: a coil formation step of forming a unipolar coil, having coil inserting portions at two positions and coil end portions at two positions, in to a shape that changes such that a size in a height direction parallel to the coil inserting portion is larger in an inner peripheral side corresponding to a diametrical direction of a motor core along a direction of awinding axis center, than in an outer peripheral side; and a coil insertion step of disposing the unipolar coil in such a manner that the coil inserting portions in the unipolar coil respectively facetoward inner peripheral opening portions of slots and are substantially parallel to an axial direction of the motor core, and inserting the coil inserting portions of the unipolar coil into the slotsbymoving the unipolar coil toward the motor core substantially linearly, while holding the motor core such that protrusion dimensions at both ends protruding from both end surface positions in an axial direction of the motor core are maintained substantially the same.