To produce a highly pure acyloxybenzoic acid in high selectivity and high yield without using a specific equipment by reacting a hydroxybenzoic acid with a lower carboxylic anhydride in the presence of a specific carboxylic acid, and subjecting the reaction mixture to the removal of the lower carboxylic acid by distillation in the presence of an acid catalyst.

A hydroxybenzoic acid of formula I [(n) is 1-3] is reacted with a carboxylic acid of formula II (R1 is a 5-21C alkyl or alkenyl, or the like) and a lower carboxylic anhydride of formula III (R2 is a 1-3C alkyl or an alkenyl), (preferably acetic anhydride) to provide a mixture of an acyloxybenzoic acid of formula IV [(h) is 1-3; (i) is 0-3; with the proviso that (h)+(i)=(n)], with a lower acyloxybenzoic acid of formula V [(j) is 1-3; (k) is 0-3; with the proviso that (j)+(k)=1-3]. The mixture is further reacted while removing the lower carboxylic acid by distillation in the presence of an acid catalyst (e.g. sulfuric acid, hydrochloric acid and nitric acid) to provide the objective highly pure acyloxybenzoic acid of formula IV without containing a polymer.