A flaw detector of a wire-rope is provided which can enhance the reliability of measurement for a damage which is located even in a deep part of the wire-rope, by detecting a leakage magnetic flux caused in a damaged part of a steel wire. The flaw detection includes a magnetizer (2) for magnetizing a wire-rope (1) in the longitudinal direction of the latter, a plurality of magnetic detection means (3, 4) arranged in the circumferential direction of the wire-rope (1), for detecting a leakage magnetic flux, storages (8, 10) previously storing therein depths of damage parts, values of damage, sums of values detected by the plurality of magnetic detection means, difference values detected by adjacent magnetic detection means, wherein a depth and a value of damage of the damaged value are obtained from the values detected by the magnetic detection means and then the value stored in the storage.