To provide a ball screw arrangement which is easy to manufacture and has high silentness.

Each top member 20 is configured to be formed with a resin. In addition, method comprises step of firstly performing temporal assembly in such a condition that disposes a plurality of ground balls 23 into a rolling pathway 17 instead of each balls on the occasion of securing each of the top member 20 to a nut 12 and then step of smoothing a boundary portion of the nut 12 and each of the top member 20 which is connection portion of the rolling pathway 17 and a circulation pathway 22 by relatively making the nut 12 and a rack shaft 3 rotate and circulating each of the ground balls 23 within the rolling pathway 17 and the circulation pathway 22.