PURPOSE: Provided is an acidic antibacterial dye which not only realizes various colors but also has antibacterial effect and thus is useful for the production of antibacterial fibers capable of preventing inflammatory diseases and bad odors.CONSTITUTION: The acidic antibacterial dye comprises a sulfonamide-based antibacterial agent to which a dye intermediate is coupled via a diazo-coupling reaction.The acidic antibacterial dye is represented by the following formula 1 wherein A is 3-methyl-1-1...