PURPOSE: To produce the subject compound suitable for an intermediate for synthesis of a coating material, etc., in a high yield without coloration or reduction of quality by reacting benzyl chloride with acetylacetone in the presence of a base in a solvent such as dimethyl sulfoxide or dimethylacetamide.

CONSTITUTION: In production of 3-benzylacetylacetone by reacting benzyl chloride with acetylacetone in the presence of a base in a solvent such as dimethyl sulfoxide or dimethylacetamide, acetyl acetone, the solvent such as dimethyl sulfoxide or dimethylacetamide and the base such as calcium carbide are charged into a reaction vessel at room temperatures and benzyl chloride is subsequently added dropwise with stirring at 80-120°C while allowing 30min. After completion of dropping, the resultant mixture is reacted at 80-120°C for 1hr, thus obtaining the objective 3-benzylacetylacetone in 100% conversion, 81% selectivity and 81% yield.