Fungicidally active novel benzylurea derivatives of the formula ##STR1## in which R.sup.1 is a halogen atom or a lower alkyl group, X is an oxygen or sulfur atom, and R.sup.2 is an alkyl group, a cycloalkyl group having 5 to 8 carbon atoms, or a phenyl group which may be substituted by at least one member of the class consisting of halogen atoms, lower alkyl groups, lower alkoxy groups and hydroxyl groups.