To insert a bolt without deformation of a screw ridge by setting the outer diameter of a cylinder of a body to be smaller than the diameter of a through hole provided on a metallic plate, and setting the inner diameter to be larger than the diameter of a threaded part.

Because the inner diameter of a body comprising a cylinder of a bolt insertion tool 1 is larger than the diameter of a threaded part of a bolt 8, the threaded part 81 of the bolt 8 can be inserted in the body cylinder. A bolt head inserted in the bolt insertion tool 1 is tapped by a hammer. A side edge of a slightly deviated through hole is pressed against an outer conical circumferential surface of a tip part of the bolt insertion tool 1, and a metallic plate is moved in the direction where the through hole is matched. Because the outer diameter of the body cylinder of the bolt insertion tool 1 is set to be smaller than the diameter of through holes 51, 61, 71 of the metallic plates 5, 6, 7, the bolt insertion tool 1 is inserted into the through holes 51, 61, 71 without any trouble.