Inorganic particles and a compound having a halosulfonyl group are made to react, bonding the halosulfonyl group to the inorganic particles. A monomer, having a functional group capable of bonding to an antibacterial compound due to the existence of the inorganic particles to which the halosulfonyl group is bonded, is graft polymerized, thus bonding a polymer, having a functional group capable of bonding to an antibacterial compound, to the inorganic particles. Next, the inorganic particles, to which is bonded the polymer having a functional group capable of bonding to an antibacterial compound, are made to react with an antibacterial compound, and the polymer bonded to the inorganic particles is transformed into an antibacterial compound, thus obtaining the antibacterial agent.
