METHOD FOR MEASURING DIMENSION OF WIRE ROD

PROBLEM TO BE SOLVED: To provide a wire rod dimension measuring method wherein diameter of a plurality of wire rods traveling side by side is sequentially measured with a single optical dimension measuring device. SOLUTION: The outside dimension of a plurality of wire rods 1-4 traveling side by side is measured with an optical dimension measuring device 10. Here, the optical dimension measuring device 10 is so shifted that the wire rods 1, 2, 3, and 4 are positioned in order at laser light ray scanning between a light projecting part 11 and a light receiving part 13 of the optical dimension measuring device 10, while the light projecting part 11 and the light receiving part 13 of the optical dimension measuring device 10 are rotated with the axis in longitudinal direction of the wire rod as a rotational center, and the wire rods 1, 2, 3, and 4 are positioned at the rotational center in order, so that the outside dimension of the wire rod is sequentially measured, in coil, over multi directions. Thus, a plurality of wire rods are measured with a single optical dimension measuring device 10. Since the outside dimension is measured continuously in coil, roundness of the wire rod is also measured.