To provide a bristle material for a brush capable of increasing stiffness of bristle and bringing the bristle material into contact with a face to be machined even if line diameter of the bristle material is small and achieving high scraping-out performance for the face to be machined and having a simple structure and simple procedures for manufacture when applying any machining such as grinding, polishing, surface treatment, washing, and deburring to the face to be machined.

This bristle material 1 for the brush for performing any machining such as grinding, polishing, surface treatment, washing, and deburring to the face to be machined forms a cross section having a plurality of core parts 2 and connects them by a wall thickness being different from the wall thickness of the core part.