To provide a bristle tip rounded device capable of efficiently rounding the bristle tips of the entire peak parts and dent parts on the chevron-shaped cut surface of a brush filling surface, uniformly finishing the entire filling part without irregularities and remarkably improving productivity in a simply constituted inexpensive form.

A grinding member is abutted to the bristle tip of the filling part B of a brush A, grinding is performed and the bristle tip is rounded. Bar members 1 arranged matched with the dent parts of the filling cut surface composed of the peak parts and the dent parts formed of the rips of the filling part B are freely rotatably provided. Then, the grinding material 2 is coated on the outer peripheral surface of the bar member 1, that is a helical bar, of a grinding bar 3 to which a grindstone is helically attached is equipped as the grinding member.