PROBLEM TO BE SOLVED: To suppress the invasion of grass and soil into an overcoming mechanism. A work unit mounted below a work machine provided with wheels, the work unit, a housing covering the work unit, a bridge unit 50 provided on the housing, and storage accommodated in the bridge unit 50. It includes an auxiliary plate 51 that is displaced to a state and a use state that protrudes from the bridge portion 50, and a flange portion 26 that is provided on the auxiliary plate 51 and extends from the upper surface of the auxiliary plate 51 to the lateral side surface of the bridge portion 50. [Selection diagram] FIG. 8【課題】乗り越え機構への草や土の侵入を抑制することを目的とする。【解決手段】車輪を備える作業機の下方に装着される作業ユニットであって、作業部と、作業部を覆うハウジングと、ハウジング上に設けられるブリッジ部５０と、ブリッジ部５０に収容される収納状態とブリッジ部５０から突出する使用状態に変位する補助板５１と、補助板５１に設けられ、補助板５１の上面からブリッジ部５０の横側面上にわたる鍔部２６とを備える。【選択図】図８
