Disclosed is an aerosol for controlling a pest insect and which has high a quick-acting ability ON the behavioral suppression of an insect and can provide a high lethal effect. Specifically disclosed is an aerosol composition for controlling a pest insect and which comprises (A) pentane, (B) a liquefied gas having a boiling point of 0C or lower and a vapor pressure of 0.3 MPa or lower at 20C and (C) at least one member selected from an ester of a fatty acid having 6 to 16 carbon atoms and an alcohol having 1 to 3 carbon atoms, an alcohol having a hydrocarbon group carrying 8 to 12 carbon atoms, and a ketone having a hydrocarbon group carrying 10 to 12 carbon atoms and wherein the ratio between the components (A) and (B) (a (a)/(b) ratio) is 5/95 to 20/80 by mass and the total content of the components (A) and (B) is 80 to 99.8 mass%.
