A benzene derivative substituted with a heterocyclic ring represented by the general formula: ##STR1## wherein R represents a cycloalkyl group having 3 to 8 carbon atoms, X represents a halogen atom, and Z represents ##STR2## in which said cycloalkyl group may be substituted with an alkyl group having 1 to 6 carbon atoms, a process for preparing the same, and a herbicidal agent comprising the above compound as an active ingredient are disclosed. The compound has an excellent effect in that the compound exhibits a markedly high herbicidal effect on weeds in the field and the paddy field at a low dose and yet exhibits markedly low noxious effects on main crops.