Insecticide compositions which comprise one or not less than two kinds of compounds being selected from a compound represented by the formula [I]: or a salt thereof, and a neonicotinoid compound represented by the formula [II]: The insecticide compositions can produce higher insecticidal effects than would be expected when each of the active ingredients is used singly, namely a synergistic effect, thus enabling reductions in the rate or number of application of agrochemicals and pesticides to be realized.