A metal wire descaling method which is a method for descaling a surface of a metal wire, comprising: conveying the metal wire in a conveyance direction that goes along an axial line of the metal wire; arranging a plurality of nozzles, each being capable of spraying a mixture of water and hard particles, respectively at a plurality of positions that are different from each other with respect to a circumferential direction of the metal wire in the surroundings of the metal wire; and descaling the surface of the metal wire by spraying the mixture of water and hard particles from the plurality of nozzles respectively onto the surface of the metal wire, wherein the plurality of nozzles include a plurality of self-cleaning nozzles, each of the plurality of self-cleaning nozzles being capable of spraying the mixture in a direction such that a spray angle θ is 90° or smaller, so that the spraying of the mixture removes an extraneous substance that is generated on the surface of the metal wire by spraying of the mixture, where the spray angle θ is an angle formed by a central axis of the spraying of the mixture from the respective self-cleaning nozzles and a vector (Vt) indicating the conveyance direction that originates at an intersection of the central axis and the surface of the metal wire, characterised in that: the plurality of nozzles include the plurality of self-cleaning nozzles and a non-self-cleaning nozzle that sprays the mixture in a direction such that the spray angle θ is greater than 90°, at least one of the plurality of self-cleaning nozzles is disposed downstream of the non-self-cleaning nozzle with respect to the conveyance direction, at least a part of a spray region of the non-self-cleaning nozzle on the surface of the metal wire with respect to the circumferential direction overlaps with a spray region of said at least one of the self-cleaning nozzles, which is disposed downstream of the non-self-cleaning nozzle, on the surface of the metal wire with respect to the circumferential direction, and the plurality of nozzles are disposed respectively at five or more positions that are lined up at an equal interval in the circumferential direction, and a nozzle that is disposed downstream of the non-self-cleaning nozzle with respect to the conveyance direction and that is adjacent to the non-self-cleaning nozzle in the circumferential direction is a self-cleaning nozzle. conveying the metal wire in a conveyance direction that goes along an axial line of the metal wire; arranging a plurality of nozzles, each being capable of spraying a mixture of water and hard particles, respectively at a plurality of positions that are different from each other with respect to a circumferential direction of the metal wire in the surroundings of the metal wire; and descaling the surface of the metal wire by spraying the mixture of water and hard particles from the plurality of nozzles respectively onto the surface of the metal wire, wherein the plurality of nozzles include a plurality of self-cleaning nozzles, each of the plurality of self-cleaning nozzles being capable of spraying the mixture in a direction such that a spray angle θ is 90° or smaller, so that the spraying of the mixture removes an extraneous substance that is generated on the surface of the metal wire by spraying of the mixture, where the spray angle θ is an angle formed by a central axis of the spraying of the mixture from the respective self-cleaning nozzles and a vector (Vt) indicating the conveyance direction that originates at an intersection of the central axis and the surface of the metal wire, the plurality of nozzles include the plurality of self-cleaning nozzles and a non-self-cleaning nozzle that sprays the mixture in a direction such that the spray angle θ is greater than 90°, at least one of the plurality of self-cleaning nozzles is disposed downstream of the non-self-cleaning nozzle with respect to the conveyance direction, at least a part of a spray region of the non-self-cleaning nozzle on the surface of the metal wire with respect to the circumferential direction overlaps with a spray region of said at least one of the self-cleaning nozzles, which is disposed downstream of the non-self-cleaning nozzle, on the surface of the metal wire with respect to the circumferential direction, and the plurality of nozzles are disposed respectively at five or more positions that are lined up at an equal interval in the circumferential direction, and a nozzle that is disposed downstream of the non-self-cleaning nozzle with respect to the conveyance direction and that is adjacent to the non-self-cleaning nozzle in the circumferential direction is a self-cleaning nozzle.