PURPOSE: An antibacterial phytoncide fiber treatment agent and an antibacterial treatment method are provided to show superior antibacterial properties and emulsification stability without harming the human body and to prevent a color change when the treatment agent is treated on a fiber. CONSTITUTION: An antibacterial phytoncide fiber treatment agent with improved emulsification stability contains phytoncide essential oil, an emulsifier, and alcohols in water. The weight of the alcohols is 1-2 times greater than the essential oil. The alcohol is ethyl alcohol. An antibacterial treatment method comprises the steps of: mixing the treatment agent and acryl-based binders; dipping a fiber or a fabric into the mixture; and heating the fiber or the fabric.본 발명은 인체에 무해하고, 항균성이 우수하며, 장시간 방치해도 유화 안정성이 우수하고 섬유 원단에 가공시 염색 색상에 변화가 없는 피톤치드 섬유 항균가공제 및 항균 가공방법에 관한 것으로서, 물에 피톤치드 정유, 유화제 및 알코올이 혼합되어 이루어지는 것을 특징으로 한다.