< Topic >Extend possibility, the auxiliary blade for the mowing machine which can disconnect also the foundation of the earth is offered to the mowing machine which cuts the grass with the surrounding revolution blade which turns around the vertical axis.SolutionsThe auxiliary blade X for the mowing machine which is provided auxiliary in the mowing machine C which cuts the grass with the rotary blade T which turns around the vertical axis, it forms with the perforation hole 11 which becomes the installation hole which is provided in the blade section 30 which is provided in the inclined section 20 which consists of the board body which from the center section 10 which consists of the level board body and the center section 10 periphery inclines to the lower part and the inclined section 20 bottom and center section 10.< Choice figure >Drawing 2【課題】鉛直軸回りに回転する囲転刃により草を刈る草刈機に追設可能な、地中の草の根も切断できる草刈機用補助刃を提供する。【解決手段】鉛直軸回りに回転する回転刃Tにより草を刈る草刈機Cに補助的に設けられる草刈機用補助刃Xを、平らな板体からなる中央部10と、中央部10外縁から下方に傾斜する板体からなる傾斜部20と、傾斜部20下端に設けられる刃部30と、中央部10に設けられる取り付け穴となる貫通孔11とにより形成する。【選択図】図2