The present invention provides a pest control composition containing a combination of (E)-1-(2-chloro- 1,3-thiazol-5-ylmethyl)-3-methyl-2-nitroguanidine and an ester compound represented by formula (1) wherein X1 and X2 each independently represent halogen, a methyl group, a trifluoromethyl group or a hydrogen atom X3 represents a hydrogen atom, a methyl group, a propargyl group, a methoxy group or a methoxymethyl group.本發明提供一種有害生物防除組成物,其含有(E)-1-(2-氯-1,3-噻唑-5-基甲基)-3-甲基-2-硝胍與下式(1)所示酯化合物之組合其中X1與X2各自獨立地代表鹵素、甲基、三氟甲基或氫原子;X3代表氫原子、甲基、炔丙基、甲氧基或甲氧甲基。
