A process for preparing a cordierite, which includes dissolving a silicon compound, an aluminum compound and a magnesium compound in a molar ratio of 1:0.7 to 1:0.3 to 0.5 in a complexing agent represented by the formula R(OCH.sub.2 CH.sub.2).sub.n OH, wherein R is an alkyl group and n is an integer of 1 to 4; heating the resulting solution to bring about a ligand exchange reaction of the silicon compound, aluminum compound and magnesium compound with the complexing agent; conducting hydrolysis to form a gel; drying the gel and sintering the dried gel at 800.degree. to 1450.degree. C.