Provided is a composition having an excellent effect for controlling harmful arthropod, comprising cyanamide compound represented by formula (I), Tricyclazole and at least one compound selected from group (A) for controlling plant diseases, Group (A): the group consisting of flutolanil, pencycuron, N-[2-(1, 3-dimethylbutyl)phenyl]-5-fluoro-1, 3-dimethyl-1H-pyrazole-4-carboxamide, furametpyr, validamycin A and kasugamycin.
