PROBLEM TO BE SOLVED: To solve such a problem that an original method for controlling insect pests by which insecticidal effects can be sustained over a long period of time even when a smoking or a heating time is shortened and is desired for a mosquito-repellent incense stick or a heating vaporizing formulation, wherein continuous use over the long period of time has hitherto been considered as a basis.SOLUTION: The method for controlling the insect pests includes: smoking or heating and vaporizing a treating chemical containing one or two or more compounds selected from among pyrethroid compounds having vapor pressure of 2×10to 1×10mmHg at 30°C as insecticidal components within 1 h changing the particle diameter of the treating chemical containing the insecticidal component vaporizing into air to ≤1 μm and providing an atmosphere which allows control of the insect pests for ≥5 h. The usefulness is particularly high in the form of the mosquito-repellent incense stick sustaining the insecticidal effects by actions of smoke.