<;P>;PROBLEM TO BE SOLVED: To provide an antibacterial agent capable of suppressing discoloration over a long term. <;P>;SOLUTION: An antibacterial metal ion (a), an inorganic compound (b) usable as a carrier of the antibacterial metal ion and a bis form of a nitrogen-containing cyclic compound (c) are contained as essential ingredients. <;P>;COPYRIGHT: (C)2008,JPO&INPIT