To provide a microbial adhesion inhibitor for a dental prosthesis excellent in microbial adhesion-inhibiting performance.SOLUTION: The microbial adhesion inhibitor for a dental prosthesis comprises a copolymer which has a constitutional unit represented by general formula (1) and a constitutional unit represented by general formula (2). The content of the copolymer is from 0.003 mass% to 1 mass% inclusive.SELECTED DRAWING: None【課題】微生物の付着抑制性能に優れる歯科補綴物用の微生物付着抑制剤を提供する。【解決手段】一般式(1)で表される構成単位、及び一般式(2)で表される構成単位を有する共重合体を含み、前記共重合体の含有量が0.003質量%以上1質量%以下である歯科補綴物用微生物付着抑制剤。【選択図】なし