This invention provides a system having superior attracting effects on harmful arthropods. Provided is a combination comprising at least one type of compound selected from the group consisting of compounds having attractiveness to harmful arthropods and at least one type of compound selected from the group consisting of compounds having repellency against that harmful arthropods, the combination being used for controlling the behavior of harmful arthropods, wherein the attracting compound and the repelling compound are used in a mode that synergistically attracts the harmful arthropods.