<;P>;PROBLEM TO BE SOLVED: To provide a method for simply and stably producing silver carbonate microparticles having &le;5 &mu;m particle diameter with a high silver content and to further provide a technique for developing antibacterial properties over a long period of time with the resultant silver carbonate microparticles. <;P>;SOLUTION: A solution A containing silver ions is mixed with a solution B containing carbonate ions in the presence of colloidal particles under specific conditions to further form a resin coating comprising the resultant silver carbonate microparticles. A heat exchanger is provided by applying the resin coating to a heat exchange part. <;P>;COPYRIGHT: (C)2009,JPO&INPIT