To prevent the scuffing/seizure by oblique integration effectively without damaging the inside of a female screw of a soft nut or the like which is made of aluminum or resin on the female screw side.

Area of a screw root part 4 of a screw end 3 of a bolt 1 is narrowed gradually from a wide area on an entrance side to form a screw thread top part 5 so that a pitch interval becomes the same as a pitch interval difference taken to be the perfect thread height gradually from an entrance side, and the pitch interval of the screw thread top part 5 narrows gradually from the start of the screw thread cutting to the perfect screw thread height. The end sectional shape with the different pitch interval is within the limit of the screw perfect thread height sectional shape and the outside flank angle of the end part is to be same angle as the perfect thread part. In a die to form the bolt 1 by rolling, a screw thread end formation processing part narrows the screw root part 4 from a wide area gradually on an entrance side, and the thread part 5 uses the die which is formed so that the pitch interval difference becomes the perfect thread height gradually from the entrance side and the pitch space becomes same.

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