To provide a microbial control agent which is excellent in microbial control performance, in particular, antimicrobial performance, anti-algae performance and biofilm formation inhibition performance, and in which elution of metal is suppressed, An acaricidal composition, an anti-mite member and a mite-proofing method.SOLUTION: The microbial control agent of the present invention comprises platinum particles and metal particles other than platinum. In addition, in the microbial control agent, the platinum particles and the metal particles may be supported on a substrate. The above microbial control agent is excellent in antibacterial performance and elution of metal is also suppressed. The miticidal composition of the present invention comprises platinum particles and metal particles other than platinum. The miticide composition is excellent in performance of suppressing the occurrence and increase of mites.Selection drawing None【課題】微生物防除性能、特に抗菌性能、防藻性能やバイオフィルム形成抑制性能に優れ、しかも、金属の溶出が抑制された微生物防除剤、並びに、ダニの発生及び増加を抑制する性能に優れ、殺ダニ組成物、防ダニ部材及び防ダニ方法を提供する。【解決手段】本発明の微生物防除剤は、白金粒子と、白金以外の金属粒子とを含む。また、上記微生物防除剤は、前記白金粒子及び前記金属粒子が基材上に担持されていてもよい。上記微生物防除剤は、抗菌性能に優れ、しかも、金属の溶出も抑制される。本発明の殺ダニ組成物は、白金粒子と、白金以外の金属粒子とを含む。上記殺ダニ組成物は、ダニの発生及び増加を抑制する性能に優れる。【選択図】なし
