Abstract: The present invention provides an amorphous porous inorganic substance having small particle sizes and uniform pores, a process for synthesizing the same, and use of the same. The invention provides an amorphous porous inorganic substance having pores of a uniform pore diameter, which has an average particle size DL of 10 to 400 nm as measured by a dynamic light scattering method and a specific surface area difference, SB−SL, between a conversion specific surface area SL calculated from DL and a nitrogen adsorption specific surface area SB obtained by the BET method, of 250 m2/g or more. A process for synthesizing the same and use of the same are also disclosed.