Chips of bone and generated cutting edge portion 131 of the large number of cutting sequentially the inner wall surface of the bone, as clump by the bone is cut can be stored for a while, the drill bit 100 of the present invention is discharged to the outside After the channel 132 a number, the drill bit 100 enters into the bone by the length of the cutting edge 131 of the number, and a working portion 130 having a blocking portion for blocking the entry of more, many channel 132 and numerous cutting edge portion 131 of the, of the bone that is formed alternately at intervals of desired in the circumferential direction with respect to the center axis 1 of the drill bit 100, is generated as hardens channel 132 of the large number part of the chip is located in front of the cutting edge 131 of the large number.本発明のドリルビット100は、骨の表面と内壁を順次に切削する多数の切削刃部131と、切削された骨によってかたまるように生成される骨のチップがしばらく保管され、外部へ排出される多数のチャネル132と、ドリルビット100が多数の切削刃部131の長さだけ骨の中に進入した後、これ以上の進入を遮断するための遮断部と、を有する作業部130を含み、多数の切削刃部131と多数のチャネル132は、ドリルビット100の中心軸1に対して円周方向に所望の間隔を置いて交互に形成され、多数のチャネル132にかたまるように生成される骨のチップの一部は、多数の切削刃部131よりも前方に位置する。
