Disclosed herein is a photocatalytic coating composition that enables control of refractive index, film density and hydrophilicity and gives a film with improved strength and adhesion. The photocatalytic coating composition comprises: (1) an alkali silicate aqueous solution having: (A) a molar ratio of silicon to an alkali (SiO.sub.2/(A.sub.2O+B) (A: alkali metal, B: NH.sub.3)) in the range of 4 to 30; and (B) a silicon concentration in terms of oxide (SiO.sub.2 concentration) in the range of 6.8 to 30% by weight; and (2) a photocatalytic compound.