To simplify machining and manufacture of a scaler chip by eliminating a sleeve in the interior of a coupling, and to improve durability and quality of the scaler chip without applying stress to a base to which a brush is adhesively bonded such as boring an opening of the base of the coupling using a drill.

A hollow part 20 is opened to one end face of the brush 2, and a connecting layer 21 for connecting the brush 2 and covering and protecting the one end face of the brush 2 is provided. The base 32 of the coupling 3 is made flat, an opening 34 for passing fluid such as water is opened in the center thereof, and the connecting layer 21 of the brush 2 is fixed to the periphery of the opening 34 of the base 32 of the coupling 3 through an adhesive 4.