The invention relates to a method for producing a (meth)acrylic anhydride A-C(═O)—O—(O═)C-A, comprising the following steps: a) a step of reacting an anhydride B—C(═O)—O—(O═)C—B with an acid A-COOH, resulting in the formation of mixed anhydride A-C(═O)—O—(O═)C—B and acid B—COOH; and b) a step of reacting the mixed anhydride with A-COOH, resulting in the (meth)acrylic anhydride. According to the invention, reaction steps (a) and (b) are carried out in the presence of hydrated triflic acid, and the anhydride A-C(═O)—O—(O═)C-A is isolated from the reaction medium produced in step (b) as follows: e1) heavy compounds having a volatility less than or equal to that of the anhydride A-C(═O)—O—(O═)C-A are separated from the reaction medium, said compounds including the anhydride and the hydrated triflic acid; e2) the anhydride is separated from the heavy compounds by difference in volatility.