A method of insect pests control characterized by, after putting insecticidal processing object in a pressure-resistant chamber, carrying out (i) reduction of pressure to a level of -0.1013 to -0.05 MPa, (ii) hermetically introducing carbon dioxide to a pressure of 0.6 to 1.0 MPa and maintaining the pressurized state for 15 to 90 min and (iii) pressure restoration through release of carbon dioxideto normal pressure and repeating the above (i) pressure reduction, (ii) pressurization and (iii) pressure restoration at least once. Further, there is provided an insect pests control apparatus for killing of insect pests living in an object through pressure reduction/pressurization/pressure restoration and through temperature control during pressurization, characterized by including a pressure-resistant chamber for accommodating the object pressure reduction means for bringing the interior of the pressure-resistant chamber to a negative pressure gas supply means for filling the interior ofthe pressure-resistant chamber with carbon dioxide to thereby attain pressurization means for pressure reduction from a set pressure to a negative pressure and temperature control means for controlling the temperature within the pressure-resistant chamber.
