The present invention provides a method for controlling weeds comprising a step of applying one or more compounds to a cultivation area of a plant, to which a gene of cytochrome P450 showing activity of metabolizing a protoporphyrinogen IX oxidase inhibitory-type herbicidal compound has been introduced, wherein said compound to be applied to said area is selected from the group consisting of: (1) flufenpyr-ethyl, (2) 2-[4-chloro-2-fluoro-5-(2-propynyloxy)phenyl]-4-methy-5-(trifluoromethyl)- -3(2H)-pyridazinone, (3) carfentrazone-ethyl, and (4) sulfentrazone; and the like.