Provided are a method and a device for descaling that make it possible to effectively remove oxide scale from the surface of a metal wire. The descaling includes spraying the surface of a metal wire (W) with a mixture (9) of water and hard particles from a plurality of nozzles (8). The plurality of nozzles (8) include a plurality of self-cleaning nozzles that spray at a spray angle (θ) of 90° or smaller with respect to the metal wire (W). The spray angle (θ) is the angle formed by the central axis (X) of the spraying and a vector (Vt) indicating a conveyance direction that originates at the intersection (P) of the central axis (X) and the metal wire surface.