THE PRESENT INVENTION AIMS TO PROVIDE A THERAPEUTIC AGENT FOR CHRONIC RENAL FAILURE, COMPRISING AS AN EFFECTIVE INGREDIENT A COMPOUND REPRESENTED BY GENERAL FORMULA (1) OR A PHARMACEUTICALLY ACCEPTABLE SALT THEREOF.THAT IS, THE PRESENT INVENTION PROVIDES PROVISION OF A DRUG COMPRISING AS AN EFFECTIVE INGREDIENT A COMPOUND REPRESENTED BY GENERAL FORMULA (1) OR A PHARMACEUTICALLY ACCEPTABLE SALT THEREOF, WHICH DRUG IS USEFUL NOT ONLY FOR AMELIORATION OF RENAL FUNCTION, BUT ALSO FOR AMELIORATION OF ANEMIA, ACTIVATION OF SOD AND EXCRETION OF UREMIC SUBSTANCES.