PROBLEM TO BE SOLVED: To provide a useful water-based insecticide composition for heat evapotranspiration for effectively pest controlling mosquitoes of which sensitivity to a pyrethroid insecticidal component is reduced, containing the pyrethroid insecticidal component and a dealing assistant for reduction of sensitivity thereto.SOLUTION: There is provided a water-based insecticide composition for heat evapotranspiration for pest controlling mosquitoes of which sensitivity to a pyrethroid insecticidal component is reduced, containing the pyrethroid insecticidal component of 0.1 to 3.0 mass%, at least one kind of glycol ether-based compound having the boiling point of 150 to 300°C as a dealing assistant for reduction of sensitivity thereto of 10 to 70 mass% and water.SELECTED DRAWING: None【課題】ピレスロイド系殺虫成分に対する感受性が低下した蚊類を有効に防除するために、ピレスロイド系殺虫成分と、これの感受性低下対処助剤とを含む有用な加熱蒸散用水性殺虫剤組成物を提供する。【解決手段】ピレスロイド系殺虫成分に対する感受性が低下した蚊類を防除するための加熱蒸散用水性殺虫剤組成物であって、ピレスロイド系殺虫成分を0.1~3.0質量%と、これの感受性低下対処助剤として沸点が150~300℃である少なくとも一種のグリコールエーテル系化合物を10~70質量%と、水とを含む加熱蒸散用水性殺虫剤組成物。【選択図】なし