PURPOSE: To easily obtain the subject compound in high yield and purity in a short reaction time without necessitating distillation and recrystallization steps by condensing 2, 6-dimethylphenol with formaldehyde in an aqueous solvent in the presence of a specific basic catalyst.

CONSTITUTION: The objective compound having high purity and good color tone compared with the color of conventional recrystallized product and useful as a polymerization raw material for the production of a high yield by (1) condensing (A) 1 mol of 2, 6-dimethylphenol to (B) 0.5-0.9 mol of formaldehyde in the presence of (C) 0.02-0.2 mol of a basic compound catalyst containing alkali metal or alkaline-earth metal in an aqueous solution to easily obtain a crude objective compound with an energy-saving process in high productivity and (2) washing the crude product with a substance selected from alcohols, ketones, esters, benzene, xylene and toluene or their mixture or a mixture of the above substance and water.