a herbicidal composition which comprises an adjuvant and an active ingredient of heterocyclic ether type phenoxy fatty acid derivative having the formula ## str1 ## wherein a represents -- ch -- or -- n --; x represents a halogen atom ; n is 0 , 1 or 2 ; r 1 represents a hydrogen atom ; a lower alkyl group ; r 2 represents -- oh ; -- o - alkyl group ; -- om group ; ## str2 ## -- o - lower alkenyl group ; -- o - benzyl group ; -- o - lower alkylalkoxy group ; -- o - phenyl ; -- o - cyclohexyl , -- o - halogenoalkyl , -- o - lower alkynyl and -- o - cyanoalkyl ; r 3 and r 4 respectively represent a hydrogen atom or a lower alkyl group .