A dispersion of alumina hydrate comprises an alumina hydrate containing 0.1 to 1.0% by weight of a nitrate anion and having an average pore radius of 20 to 200 .ANG. and a half breadth of pore radius distribution of 20 to 150 .ANG. and deionized water. Another dispersion of alumina hydrate comprises an alumina hydrate containing 0.1 to 1.0% by weight of a nitrate anion and having at least two peaks in pore radius distribution and deionized water. Another dispersion of alumina hydrate comprises a titanium dioxide-containing alumina hydrate containing 0.1 to 1.0% by weight of a nitrate anion and deionized water. In each of these dispersions, when the alumina hydrate is dispersed in water at a solids concentration of 15% by weight to form a dispersion, the viscosity of the dispersion is not higher than 75 cP as measured at 20.degree. C. and the dispersion has a shear rate of 7.9 sec.sup.-1.