Submicro-sized uniform silica particles were prepared by low-temperature sol-gel process using tetraethoxy silane (TEOS). The silica particle was sized about 560 nm and was homogeneously sphere-shaped. The surface of silica particle was functionalized with hydroxyphenylbenzoxazole for a response to phosphate-nerve gases such as Sarin, Soman, and Tubun. Fluorescence spectra of suspension of the functionalized silica particle were significantly changed by exposure to nerve gas model compound, which showed fluorescence quenching.