A wire rope flaw detector comprises a back yoke (3) and excitation permanent magnets (4a, 4b), which form a main magnetic path in a predetermined section of a wire rope (1) in the axial direction; a magnetic path member (7) arranged in the predetermined section to be magnetically insulated from the back yoke (3) and the permanent magnets (4a, 4b) and making the leakage flux generated from a damaged part (10) of wire rope detour to the outside of the wire rope (1); and a detection coil (8) wound around the magnetic path member (7) for detecting leakage flux. The amount of leakage flux can be increased by providing the magnetic path member (7) and since the windable area of the detection coil (8) is increased, the number of turns of detection coil can be increased.