Anti-bacterial composite particles which comprise a polymer base material comprising a thermal melting polymer, such as a polyolefine, exhibiting good dispersibility in a basic material resin and having a lower molecular weight or a lower softening point than that of the basic material resin, and inorganic fine particles comprising a metal having anti-bacterial activity carried thereon. An antibacterial resin composition can be prepared by melting and kneading a synthetic resin composition as the basic material resin together with the anti-bacterial composite particles and forming by known molding methods such as extrusion molding and injection molding, and can be used for producing various synthetic resin moldings which have an inorganic anti-bacterial agent uniformly dispersed in a synthetic resin composition and thus exhibits good anti-bacterial effect.