To provide a securing structure of a channel brush capable of securing a channel brush by a simple, speedy and easy process without a possibility of the channel brush coming off from a retainer even if an impact etc. is applied on the brush from outside.

The securing structure 1 of a channel brush 2 used for grinding, polishing, surface treating, cleaning, and deburring the surface of a workpiece is composed of the channel brush 2, a retainer 3 and a base 4. The channel brush 2 may be composed of a brush piece 5, a core wire 6, and a strip-like body 7, or may be composed of the brush piece 5 and the strip-like body 7. The retainer 3 is formed by forcedly fitting the brush piece 5 inside, and fixed to the base 4, and thus, the channel brush 2 is sandwiched between the retainer 3 and the base 4.