To provide silica-based particles with a low refractive index, the hollow and spherical silica-based particles include porous materials or cavities inside an outer shell thereof by growing porous composite oxide particles (primary particles) adjusting a ratio of a quantity of added silica sources versus a quantity of added sources for an inorganic oxide other than silica and then removing the inorganic oxide other than silica. The dispersion liquid of silica-based particles is aged at a range from the room temperature to 300° C., cleaning is performed according to the necessity, and hydrothermal processing is performed at a temperature in the range from 50 to 300° C.