PROBLEM TO BE SOLVED: To provide an antifungal agent containing a polymer having excellent antifungal performance. An antifungal agent containing a cationic group-containing copolymer, wherein the antifungal agent has an antifungal ability of 2.0 or more as measured by a specific method using black mold, and a cationic group. The containing copolymer has the structural unit (a) derived from the cationic group-containing monomer (A) and the structural unit (b) derived from the monomer (B), and the proportion of the structural unit (a) is Is from 36 to 99.9% by mass based on 100% by mass of all structural units, and the monomer (B) is a monomer (B1) having a homopolymer solubility parameter of 10 or less, and A copolymer containing a cationic group, which is one or more kinds of monomers selected from a monomer (B2) having at least one kind of functional group selected from the group consisting of a carboxyl group, a hydroxyl group and an ether group. The antifungal agent has a weight average molecular weight of 4000 to 1,000,000, and the proportion of the cationic group-containing copolymer is 10 to 100% by mass relative to 100% by mass of the antifungal agent. [Selection diagram] None【課題】抗カビ性能に優れる重合体を含む抗カビ剤の提供。【解決手段】カチオン性基含有共重合体を含む抗カビ剤であって、抗カビ剤は、クロカビを用いた特定の方法により測定される抗カビ能が２．０以上であり、カチオン性基含有共重合体は、カチオン性基含有単量体（Ａ）由来の構造単位（ａ）と単量体（Ｂ）由来の構造単位（ｂ）とを有し、前記構造単位（ａ）の割合が、全構造単位１００質量％に対して３６～９９．９質量％であり、単量体（Ｂ）は、単独重合体の溶解性パラメータが１０以下である単量体（Ｂ１）、並びに、カルボキシル基、水酸基及びエーテル基からなる群より選択される少なくとも１種の官能基を有する単量体（Ｂ２）、から選択される１種以上の単量体であり、カチオン性基含有共重合体の重量平均分子量が４０００～１００万であり、カチオン性基含有共重合体の割合が抗カビ剤１００質量％に対して１０～１００質量％である抗カビ剤。【選択図】なし
