PURPOSE: To give a screw material having enough binding torque strength, by placing at least one layer of the cylindrical knitting knitted with reinforcing fiber bundles extending over a flight of the outer or inner surface of the screw member and a neighboring screw core part.

CONSTITUTION: Two layers 5a, 5b of a cylindrical knitting are placed in a bolt 1 and more than one of fiber bundles 6 consisting of reinforcing-fibers are placed in the core part of the bolt 1. The reinforcing fibers are cured with a resin 7 and the cylindrical knitted string 5a located in the outermost layer extends over a screw part 2 and the position 3a of the core part 3 neighboring to the screw part 2. The fiber bundles constituting the cylindrical knitted strings 5a spread over the screw part 2 and the core part 3 and the screw part 2 is thereby firmly joined with the core part 3. The screw part 2 of the bolt 1 therefore has high shear strength.