Excellent microbial control performance, especially antibacterial performance, algae control performance and biofilm formation suppression performance, microbial control agent with suppressed metal elution, and excellent performance to suppress the occurrence and increase of ticks, miticide composition Article, tick-proof member and tick-proof method are provided. The microorganism control agent of the present invention contains platinum particles and metal particles other than platinum. Moreover, as for the said microorganisms control agent, the said platinum particle and the said metal particle may be carry supported on the base material. The above-mentioned microorganism control agent is excellent in antibacterial performance and also suppresses metal elution. The acaricidal composition of the present invention contains platinum particles and metal particles other than platinum. The said acaricidal composition is excellent in the performance which suppresses generation occurrence production and increase of a tick.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。 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。
