PROBLEM TO BE SOLVED: To provide a biofilm formation inhibitor that does not damage piping or devices and is also safe for human bodies.SOLUTION: A biofilm formation inhibitor contains, as an active ingredient, at least one quinone compound selected from the group consisting of hydroquinone substituted with a hydroxy group or an alkyl group, and p-benzoquinone substituted with a hydroxy group or an alkyl group.SELECTED DRAWING: NoneCOPYRIGHT: (C)2018,JPO&INPIT【課題】配管や機器に損傷を与えることがなく、かつ人体にも安全なバイオフィルム形成抑制剤の提供。【解決手段】水酸基又はアルキル基で置換されたヒドロキノン、及び水酸基又はアルキル基で置換されたp-ベンゾキノンからなる群より選択される少なくとも1種のキノン化合物を有効成分とする、バイオフィルム形成抑制剤。【選択図】なし