PURPOSE: To aim at shortening the time of change of cutting blades, by providing a carrier vehicle having a sawing machine, movably back and forth, on each of a pair of base carrier vehicles between which is disposed a sawing line orthogonal to a steel wire material conveyor line and which travels in parallel with the conveyor line, so that either one of the carrier vehicles is used as a spare.

CONSTITUTION: In order to change a saw 3 on a sawing machine 2A with a new one due to abrasion, etc., a carrier vehicle 10 for the sawing machine 2A moves backward under the pressure of the rod side of a cylinder 12 to a backward limit L2 and comes to a stop, and after a slidable part 11C of a basic carrier vehicle 11 for the sawing machine 2A and clamp plates 23 are released from the pressure of the rod sides of cylinders 21, the basic carrier vehicle moves by a predetermined distance in the direction X due to rotation of a motor 30. Then, the clamp plates 23 again fixes the slidable part 11 under the ram pressure of the cylinders 21. Then, as to a sawing machine 2B, after the slidable member 11C is released from the clamp plates 23 by means of the cylinders 21, the sawing machine 2B is moved by a predetermined distance in the direction X, the center position of a saw 3 on the sawing machine 2B being aligned with the center position of sawing, and then the sawing machine 2B is advanced to a predetermined position by the cylinder 12 in the direction Y to perform a new sawing step, thereby a rapid change of cutting blades may be made.