An object of the present invention is to provide a biofilm inhibitor composition capable of suppressing formation of a biofilm in a washing machine and suppressing odor in a washing tub. A component (A): an antibacterial agent which is a hydroxydiphenyl ether compound； a component (B): an enzyme group containing an amylase and an enzyme other than an amylase； and a component (C): a water-miscible organic solvent. A biofilm inhibitor composition, wherein the content of the component (C) is more than 5% by mass and 20% by mass or less based on the total mass. [Selection diagram] None【課題】本発明は、洗濯機内のバイオフィルムの形成を抑制し、洗濯槽の臭気を抑制できるバイオフィルム抑制剤組成物を目的とする。【解決手段】（Ａ）成分：ヒドロキシジフェニルエーテル化合物である抗菌剤と、（Ｂ）成分：アミラーゼとアミラーゼ以外の酵素とを含む酵素群と、（Ｃ）成分：水混和性有機溶剤と、を含有し、前記（Ｃ）成分の含有量が総質量に対して、５質量％超２０質量％以下である、バイオフィルム抑制剤組成物。【選択図】なし
