An acoustical rating for the occupied hall of our National Theatre is presented for symphony orchestra and opera by theoretical estimation of various acoustical qualities from the basis of measured reverberation times in its vacant stste. The result is that by serious poverty of liveness a romantic music, typical symphony orchestra and even classical music are very difficult to be performed and only a baroque music is scarcely allowable to be performed in this hall. As for opera, wagnerians are difficult and italians are performable to some extent. Some discussions are given for which defects are more serious in this hall and some possible accustical corrections are also suggested for its better performance.