Complexes between TiO₂ and sugar alcohol molecules or polyol molecules were prepared by heating the mixture of titanium isopropoxide (TIP) and ethylene glycol, glycerin, meso-erythritol, or D-mannitol aqueous solution at 368 K for 24 h. The degree of crystallization of TiO₂ in the obtained TiO₂-sugar alcohol or polyol complex depended on the concentration of the polyol and sugar alcohol aqueous solution. When the TiO₂-sugar alcohol or polyol complex was prepared by using the same concentration of the sugar alcohol or polyol aqueous solution, the degree of crystallization of the TiO₂ in the complex decreased with increase in the number of OH groups per molecule. According to the results of the DTA measurements and the element analysis, the strength of the interaction between Ti⁴⁺ ions and polyol or sugar alcohol molecules increased with increases in the number of OH groups in the molecules. The heat treatment of TiO₂-D-mannitol complex in 0.5 mol/l HNO₃ aqueous solution at more than 318 K enabled to obtain TiO₂-D-mannitol complex nanoparticles by breaking the bonds between the D-mannitol molecules and Ti⁴⁺ ions. The obtained TiO₂-D-mannitol complex nanoparticles had large surface area which was more than 300 m²/g and showed photocatalytic activity. Furthermore, the complex nanoparticles can be dispersed into the distilled water with high stability.