PROBLEM TO BE SOLVED: To provide a boom spreader that variably adjusts a spraying width by adjusting a boom length so as to match a boundary line of a spraying planned area, by considering a traveling speed of a machine body and a boom extension/contraction speed, Prevents spraying and leakage of sprays in the planned spraying area. SOLUTION: The boom spraying device includes a control unit 20 that controls a spraying width in accordance with position information of an airframe based on a GPS signal, and the control unit 20 sprays a boundary line of a preset spraying area 24 and a spraying region. When the boom length is controlled to expand and contract so that the width ends match, and the recognized traveling speed of the aircraft exceeds the set speed determined by the speed at which the boom length is extended and contracted, the traveling speed of the aircraft. One or both of a warning signal for prompting a reduction and a control signal for reducing the traveling speed of the machine body are output. [Selection diagram] Fig. 4【課題】散布予定領域の境界線に合わせるようにブーム長さの調整によって散布幅を可変に調整するブーム散布装置において、機体の進行速度とブームの伸縮速度を考慮することで、散布予定領域外の散布や散布予定領域内の散布漏れを抑止する。【解決手段】ブーム散布装置は、ＧＰＳ信号に基づく機体の位置情報に応じて散布幅を制御する制御部２０を備え、制御部２０は、予め設定されている散布予定領域２４の境界線と散布幅の端が合致するように、ブームの長さを伸縮制御し、認識される機体の進行速度が、ブームの長さを伸縮させる速度によって決まる設定速度を超えた場合には、機体の進行速度低減を促す警報信号と機体の進行速度を低減させる制御信号の一方又は両方を出力する。【選択図】図４
