Abstract: A plurality of bristle and core wire combination bodies each comprising a bristle of resilient wire formed into the shape of coil and a core wire of metal passed through the loops of the bristle are formed. The same number of other core wires of metal as the combination bodies are prepared. A core wire assembly is formed by twisting alternately the core wires of said combination bodies and the other core wires. A twisted wire body is formed by twisting the core wire assembly continuously in the longitudinal direction, in which a large number of loops of the bristles are arranged in a spiral shape in the longitudinal direction along the twist of the core wires. A plurality of rows of spiral brush bristles are formed by cutting the loops of the bristles of the twisted wire body.