PURPOSE: To prepare the titled compound useful as an intermediate of pharmaceuticals and agricultural chemicals, in high conversion, with little side reactions, by oxidizing an arylalkylmethane with an oxygen-containing gas in the presence of an aqueous solution of caustic alkali and a boron compound in the reaction system.

CONSTITUTION: An α-aryl tertiary alcohol of formula II is prepared by introducing an oxygen-containing gas into the reaction system containing an aryldialkylmethane of formula I (X is H, halogen such as Cl, Br, etc., alkyl such as methyl, ethyl, etc. or alkoxy such as methoxy, ethoxy, etc.; n is 1W3; R1 and R2 are lower alkyl) in the presence of an aqueous solution of a caustic alkali such as NaOH, KOH, etc. The reaction is carried out in the presence of a boron compound (e.g. borax, sodium perborate, metaboric acid, potassium borate, boric anhydride, etc.) at ≥80°C, preferably 90W130°C. The reaction proceeds in high efficiency. Since the reaction product is free from peroxide, etc., the post-treatment of the product can be carried out safely.