The present invention provides a defect grinding method for round steel by which a defect portion of round steel can be automatically ground without causing such error grinding that a position of the defect portion and a grinding position are misaligned, and a manufacturing method for steel. A defect grinding method for round steel is provided with: a marking step (Step S2) for coating, with a marking M, a defect portion having a predetermined depth or more, which has been subjected to flaw detection in a flaw detection step (Step S1); a defect portion map creation step (Step S3) for creating a defect portion map (50) from a flaw detection result in the flaw detection step; and a defect portion grinding step (Step S4) for grinding the defect portion. In a marking spot grinding step (Step S47) in the defect portion grinding step, grinding positioning of a round steel S in a longitudinal direction is decided by referring to the defect portion map (50). Grinding positioning of the round steep S in a circumferential direction is decided by referring to an extraction result for the marking (M) by the marking detection step (Step S46). A grinding depth is decided by checking the defect portion map (50) and the extraction result for the marking (M).
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