PROBLEM TO BE SOLVED: To provide a plant growth promotion device which allows growth promotion and sterilization without changing the composition of the culture medium by applying both an electric field for growth promotion and an electric field for sterilization while the size of the required power source is reduced.SOLUTION: The present invention comprises: a power source 105 which can apply a short pulse voltage of 5 microseconds or less as the time the voltage is held at 50% or more than the voltage peak value； and a switch 108 for switching the connection between a pair of growth promotion electrodes 106 and a pair of sterilization electrodes 107 with respect to a power source. Roots 101a of the plant 101 are present between the growth promotion electrodes and the roots of the plant are not present between the sterilization electrodes.SELECTED DRAWING: Figure 1【課題】 成長促進用電界印加と殺菌用電界印加との両立により、必要な電源を小型化し、さらに培養液の組成を変化させること無く成長促進と殺菌とが可能である植物成長促進装置を提供する。【解決手段】 電圧ピーク値から５０％以上の電圧を保持する時間が５マイクロ秒以下の短パルス電圧を印加できる電源１０５と、電源に対する一対の成長促進用電極１０６と一対の殺菌用電極１０７との接続を切り替えるスイッチ１０８を有し、成長促進用電極間には植物１０１の根１０１ａが存在し、殺菌用電極間には植物の根が存在しない。【選択図】図１
