It possesses the strong antimicrobe and mildewproofing operation, it does not show irritating odor and skin irritation when furthermore is easy to evaporate, evaporates, the antimicrobe for the new vapor phase which can be used safely in the vapor phase, it offers the antifungal agent.General expression< Conversion 1 >(As for R the carbon count the alkyl group or carbon count the arukeniru basis or carbon count the aralkyl basis of 7 of 2 of 1 the numerator chain may be suspended with the nitrogen atom or the sulfur atom - 6 - 6 - 13, R is the hydrogen atom, or or the carbon count alkyl group 1 the numerator chain may be suspended with the nitrogen atom or the sulfur atom - 4) with it is displayed, the antimicrobe for the vapor phase which at the same time designates evaporation possible isochioshianatoaseteto chemical compound as the active ingredient under working condition, it makes the antifungal agent.強い防菌、防黴作用を有し、しかも気化しやすく、気化した状態で刺激臭や皮膚刺激性を示さず、気相中において安全に使用できる新規な気相用防菌、防黴剤を提供する。一般式【化1】(R1は分子鎖が窒素原子又は硫黄原子で中断されていてもよい炭素数1~6のアルキル基若しくは炭素数2~6のアルケニル基又は炭素数7~13のアラルキル基、R2は水素原子であるか、或いは分子鎖が窒素原子又は硫黄原子で中断されていてもよい炭素数1~4のアルキル基)で表わされ、かつ使用条件下で気化可能なイソチオシアナトアセテート化合物を有効成分とする気相用防菌、防黴剤とする。