Improvement of the effect of a herbicidally active ingredient and reduction of its dosage are required so as to reduce the environment load on a site where the herbicide is applied or the periphery thereof, more than ever. A herbicidal composition comprising (1) a herbicidal sulfonylurea compound or its salt and (2) a polyoxyalkylene alkyl ether phosphate or its salt. A method for controlling undesired plants or inhibiting their growth, by applying such a herbicidal composition.