PURPOSE: To obtain the compound, having hemostatic actions in bleeding animal bodies and useful as medicines, etc., for human bodies by oxidizing a specific methylnaphthalene with an oxidizing agent such as hydrogen peroxide.

CONSTITUTION: This method for producing 2-methyl-1,4-naphthoquinone is to react (A) 2-methylnaphthalene with (D) hydrogen peroxide [preferably in an amount of 1-4mol based on 1mol component (A)] and/or an organic peracid in the presence of (C) a palladium compound (preferably a palladium compound soluble in the reactional system, e.g. palladium acetate) and sulfuric acid in an amount of 5-100g based on 1l of (B) a solvent containing a carboxylic acid (preferably a ≤8C saturated aliphatic carboxylic acid, e.g. acetic acid) in the solvent of the component (B), e.g. at 40-90°C temperature for about 5min to 8hr.