To obtain a herbicide composition having an excellent herbicidal activity by including oxadiargyl, simetryn, and dimethametryn.

This composition is obtained by including (A) 5-tert-butyl-3-(2,4- dichloro-5-propargyloxyphenyl)-1,3,4-oxadiazole-2-(3H)-one (common name 'oxadiargyl') shown by formula I and (B) 2-methylthio-4,6-bis(ethylamino)-S- triazine (common name 'simetryn') shown by formula II and/or (C) 2- methylthio-4-ethylamino-6-(1,2-dimethylpropylamino)-S-triazine (common name 'dimethametryn') shown by formula III. It is preferable that the composition contains component(s) B and/or C 0.1-10 time(s) (w/w) component A, and that the amount of application of the composition is 1-1,000 g-active ingredient/10a.