To provide a colloidal solution stably dispersed in water, substantially containing only a compound represented by general formula: [M2+1-xM3+x(OH)2]x+ and monovalent inorganic anions, and useful for a catalyst, etc., and to provide a method for producing the same.

The aqueous dispersion type colloidal solution is prepared by sophisticatedly reacting a mixed aqueous solution of a divalent metal salt and a trivalent metal salt with an aqueous alkali solution and dispersing in water a layered double hydroxide synthesized by coprecipitating the divalent metal salt and the trivalent metal salt by the reaction. The colloidal solution substantially contains only a compound represented by the general formula: [M2+1-xM3+x(OH)2]x+ and monovalent inorganic anions, wherein a molar ratio of the monovalent inorganic anions to the compound is in a range of 0.1-0.4. In the general formula, M2+ represents a divalent metal ion; M3+ represents a trivalent metal ion; and x is in a range of 0.13<x<0.28.