PROBLEM TO BE SOLVED: To prevent pollution of air taken into the interior from the exterior.SOLUTION: The ventilation system (10) for plant cultivation facilities includes a casing (11) in which an inlet (12) for taking in exterior air and an air outlet (13) are formed, and a blower fan (15). Exterior air is taken into the casing (11) and treated, and the treated air is fed into a greenhouse (1) for plant cultivation facilities from the outlet (13). The ventilation system also includes: a dust collection device (20) disposed within the casing (11) for removing dust in the taken-in air; a discharge device (60) having a water storage tank (61) for storing water, an electrode pair (64 and 65) for generating streamer discharge under water in the water storage tank (61) and a power supply (70) for applying the direct voltage to the electrode pair (64 and 65), and configured to generate hydrogen peroxide under water in the water storage tank (61) by the streamer discharge; and a spray unit (30) for feeding water containing hydrogen peroxide within the water storage tank (61) to a dust collection part (25).【課題】室外から室内へ取り込む空気の汚染防止対策。【解決手段】植物栽培施設用の換気装置(10)は、室外空気の吸込口(12)と空気の吹出口(13)とが形成されたケーシング(11)と送風ファン(15)とを備え、室外空気をケーシング(11)内に取り込み、取込空気を処理して処理空気を吹出口(13)から植物栽培施設用のハウス(1)内に供給するものであって、ケーシング(11)内に設けられ、取込空気中の塵埃を除去する集塵装置(20)と、水を貯留する貯水タンク(61)、貯水タンク(61)の水中でストリーマ放電を生起する電極対(64,65)、及び電極対(64,65)に直流電圧を印加する電源部(70)を有し、ストリーマ放電によって貯水タンク(61)の水中に過酸化水素を生成する放電装置(60)と、貯水タンク(61)内の過酸化水素を含む水を集塵部(25)に供給する噴霧ユニット(30)とを備えている。【選択図】図2