PROBLEM TO BE SOLVED: To provide a structure for preventing winding of grass and straw of a rotary tiller which can prevent a long-culm such as grass and straw from being wound around a cultivating shaft without installing a linear member.SOLUTION: The rotary tiller includes a plurality of cultivating claw mounting bodies that are mounted to an outer periphery of the cultivating shaft so as to be protruded while separating apart from each other in the axial direction thereof, where a base end part of a cultivating claw is mounted to each cultivating claw mounting body. In the rotary tiller, a grass and straw winding prevention body that extends a diameter of the cultivating shaft by surrounding the outer periphery of the cultivating shaft can be optionally disposed between the cultivating claw mounting bodies adjacent to each other in the axial direction of the cultivating shaft.COPYRIGHT: (C)2015,JPO&INPIT【課題】線状部材を設けることなく、耕耘軸への草や藁の長稈巻き付きを防止することができるロータリ耕耘装置の草藁巻付防止構造を提供すること。【解決手段】耕耘軸の外周面に、その軸線方向に間隔をあけて複数の耕耘爪取付体を突出状に取り付けて、各耕耘爪取付体に耕耘爪の基端部を取り付けたロータリ耕耘装置であって、耕耘軸の軸線方向に隣接する耕耘爪取付体間に、耕耘軸の外周面を囲繞して耕耘軸を大径化する草藁巻付防止体を後付け可能とした。【選択図】図5