Provided is a method for producing an antimicrobial composition of excellent solubility in water. A method for producing an antimicrobial composition, the method comprising a step for heat-treating at 100-180°C a phenolic antimicrobial (A) and a water-soluble aromatic compound (B) in the presence of an aqueous vehicle.本發明提供一種製造於水中之溶解性優異之抗菌劑組合物之方法。該抗菌劑組合物之製造方法包含於水性介質之存在下,在100~180℃下加熱處理(A)酚系抗菌劑與(B)水溶性芳香族化合物之步驟。