A magnetic flux generated by current excitation is allowed to pass through a part or an entire of a magnetic path of a leakage magnetic flux. A magnetic flux content due to the current excitation is temporally changed to change a leakage magnetic flux content interlinked with a detection coil so that an induced voltage is generated in the detection coil. Consequently, damage can be detected even in a case where there is no relative speed between a wire rope and a wire rope flaw detector. Further, a configuration of the magnetic path and the number of ampere turns of an exciting coil are set to be appropriate to prevent the magnetic flux generated by the current excitation from passing through the detection coil or to allow the magnetic fluxes offset each other. Thus, noise superimposition on the detection coil due to the current excitation can be prevented.