The purpose of the present invention is to provide: a harmful organism control composition which contains a combination of a novel pyridone compound or a salt thereof and a harmful organism control agent and can exhibit a useful controlling effect; and a method for using the harmful organism control composition. Provided is a harmful organism control composition which contains, as active ingredients, a compound represented by formula (1) or a salt thereof and at least one component having a harmful organism controlling activity and selected from harmful organism control agents. In the formula, R1 represents a C1-C6 alkyl group which may be substituted, a C1-C6 haloalkyl group, or the like; R2 represents a halogen atom, a C1-C6 alkyl group which may be substituted, a C1-C6 alkoxy group which may be substituted, or the like; R3 represents a hydrogen atom, a halogen atom, a C1-C6 alkyl group which may be substituted, or the like; n represents an integer of 0 to 5; X represents an oxygen atom or a sulfur atom; Y
