The present invention relates to an amine derivative represented by the following chemical formula (I) (wherein Ar is a phenyl group, R1 is a hydrogen atom, R2 is a C1-6 alkylcarbonyl group, R3 is a C1-8 alkylene group, etc., R4 is And a pest control agent comprising at least one of the derivatives. It has been found that the amine derivative has an excellent activity as a control agent for agricultural and horticultural pests.本発明は、下記化学式(I)で示されるアミン誘導体(式中Arはフェニル基等、R1は水素原子等、R2はC1~6アルキルカルボニル基等、R3はC1~8アルキレン基等、R4は水素原子等を示す。)、及び、当該誘導体を少なくとも1種以上含んでなる有害生物防除剤に関する。当該アミン誘導体は、農園芸上の害虫に対する防除剤として優れた活性を有することを見出した。