The present invention provides an N-sulfonyl carboxylic amide derivative including an N-containing 6-membered aromatic ring represented by formula [I]: ##STR1## wherein R.sup.1 represents an alkyl group, an alkenyl group, or the like, R.sup.2 represents a hydrogen atom, an alkyl group, or the like. R.sup.3 and R.sup.4 represent independently an alkyl group or a nitrogen atom; or the salt of the same, a method for producing the same, and a biocide containing the same as an active ingredient. The N-sulfonyl carboxylic amide derivative including an N-containing 6-membered aromatic ring according to the present invention exhibits superior effects against blight caused by plant pathogenic fungi belonging to Oomycetes such as downy mildew, late blight, or the like in a low concentration as well as controls weeds occurring in paddy fields and plowed fields.