PROBLEM TO BE SOLVED: To provide a tilling working machine which prevents mud and dirt from penetrating a rear cover and does not reduce working efficiency. SOLUTION: Space portions 30b, 32b, 35b are formed by folding back a sheet metal material at a lower end portion of a rear cover 29 that covers the rear of the tilling claws 23, 23... Rotating around a tilling shaft 22. The gap member 41 is put in 35b so that at least the inlets of the spaces 30b, 32b, 35b are closed. The gap member 41 is made of a material whose specific gravity is smaller than the specific gravity of the lower end component member of the rear cover 29. [Selection diagram] Fig. 3【課題】リヤカバーの泥土浸入を防いで作業効率等の低下を来さない耕耘作業機を提供すること。【解決手段】耕耘軸２２回りに回転する耕耘爪２３，２３…の後方を覆うリヤカバー２９の下端部に板金材の折り返しによる空間部３０ｂ，３２ｂ，３５ｂを形成し、この空間部３０ｂ，３２ｂ，３５ｂに隙間材４１を入れ、少なくとも空間部３０ｂ，３２ｂ，３５ｂ入口を塞ぐよう構成する。また、前記隙間材４１は、その比重がリヤカバー２９の下端部構成部材の比重よりも小さい素材とする。【選択図】図３
