To provide a pruning unit capable of solving problems for example, in a pruning unit for performing pruning and delimbing while going around a tree to a tree which is an object of pruning, force is also required in a direction for pressing and expanding a cut area of a branch, especially when a branch diameter is increased, it is estimated that force for pressing and expanding which is proportional to almost cube of the branch diameter is required, so that a branch diameter of a branch to be cut may be significantly restricted and required power is also increased.SOLUTION: There is provided a pruning unit which can set an immersion angle ξ of an electrically driven chain saw in pruning according to a trunk diameter of a tree while maintaining an almost constant interval between the electrically driven chain saw and a trunk surface of an object tree.SELECTED DRAWING: Figure 3【課題】枝打ち対象の樹木に対して、樹の周りを周回しながら枝打ち・枝払いをする枝打ち装置にあっては、枝の切り口を押し広げる方向にも力を必要とする。特に枝径が増加するに際して、ほぼその３乗に比例した押し広げ力がかかると考えられるので、切断対象の枝径が大幅に制限されるおそれがあり、要求される電力も増大する。これらの課題を解決する枝打ち装置を提供する。【解決手段】電動チェーンソーと対象樹木の幹表面との間隔を略一定に保ちつつ、枝打ち時における電動チェーンソーの侵入角度ξを、樹木の幹径に応じて設定する枝打ち装置。【選択図】図３
