A heterocyclic cyclohexanedione derivative represented by the general formula I!: ##STR1## wherein R.sup.1 is optionally substituted lower alkyl, optionally substituted cycloalkyl, optionally substituted phenyl or optionally substituted heterocyclic ring; R.sup.2, R.sup.3, R.sup.4 and R.sup.5 may be the same or different from one another and each independently represents hydrogen or lower alkyl; R.sup.6 is hydrogen; R.sup.7 is OR.sup.8 wherein R.sup.8 is hydrogen, lower alkyl, aralkyl, lower acyl, alkylsulfonyl or arylsulfonyl; or R.sup.6 and R.sup.7 are combined together to represent a single bond; X is oxygen, sulfur or N--R.sup.9 wherein R.sup.9 is hydrogen, lower alkyl, optionally substituted aralkyl, optionally substituted cycloalkyl, optionally substituted phenyl or optionally substituted heterocyclic ring, a salts thereof, a process for producing the same, and a herbicides comprising the same.