Avermectin derivatives represented by the general formula (I) or salts thereof: wherein —X----Y— represents —CH═CH—, —CH2—C(═O)—, —CH2—CH2—, or —CH2—CH(R13)—; for example, 1) when —X----Y— represents —CH═CH—, R1 represents (R11)(R12)C [wherein R11 represents a substituted or unsubstituted lower alkyl group; a formyl group; a lower alkoxylcarbonyl group etc.; and R12 represents a hydrogen atom or a lower alkyl group]; when the bond between R2 and a carbon atom at the 5-position is a single bond, R2 represents a hydroxyl group or a tri(lower alkyl)silyloxy group; or R2 forms a carbonyl group or a hydroxime group together with the carbon atom at the 5-position; 2) when —X----Y— represents —CH2—C(═O)—, R1 represents (R11a)(R12a)C [wherein R11a represents a lower alkoxycarbonyl group, or —COOCH2CH═CH2; and R12a represents a hydrogen atom]; and R2 represents a hydroxyl group or a tri(lower alkyl)silyloxy group.