A new photochromic spiroxazine dye having a pyridinium s-triazine moiety has been prepared. It shows a reversible photochemical color change from colorless to reddish-purple in ethanol solution. In ethanol solution the half life time of the open form was 150sec, which was shortened by raising temperature. Silica-immobilized spiroxazine(6). Fine power of silica-immobilized spiroxazine was changed intensely blue from colorless by U.V. light or sunlight.