A magnetic inspection device and method for nondestructive testing of wire ropes and the like utilizes a leakage flux generator moveable relative to a wire rope to be inspected for inducing in sections of the wire rope magnetic flux at a saturation level. A leakage flux detector moves with the leakage flux generator, and cooperates with the leakage flux generator for detecting leakage flux at the outer surface of the wire rope saturated by the generator. The detector provides a high fidelity signal representative of the loss of metallic cross section at individual locations along the wire rope. A signal processor receiving the high fidelity signal representative of the loss of metallic cross section from the detector extracts a wire rope roughness component from the high fidelity signal.