PURPOSE: To highly selectively obtain a 1-nitroanthraquinone in high yield by introducing a gas such as nitrogen to the reaction system in nitrating an anthraquinone with sulfuric acid and nitric acid.

CONSTITUTION: An anthraquinone of formula I (X is a halogen, a 1-4C alkyl, a 1-4C alkoxy, OH, carboxyl or sulfonic group substituted at the 1-, 2-, 3- or 4-position; (m) and (n) are each 0-3; Y is the same group as that of X which is substituted at the 5-, 6-, 7- or 8-position) is nitrated with sulfuric acid and nitric acid to give a 1-nitroanthraquinone of formula II. In the reaction, a gas (especially nitrogen, helium, argon, carbon dioxide, especially preferably nitrogen) is introduced into the system to carry out the reaction. Anthraquinone and l-bromo-3-anthraquinonesulfonic acid are especially preferable as the anthraquinone.