The characteristics of the removal of gaseous elemental mercury using activated carbon injection in a particulate collector with fabric filters were experimentally estimated. The experiments showed that, at given conditions in this research, the removals of elemental mercury converged to a certain level as activated carbon continued to be injected irrelatively to the C/Hg ratio or the types of activated carbon. When the C/Hg ratio was fixed at 7000, the elemental mercury removal by the activated carbon collected on the filter surface was 9.5% of the total elemental mercury removal at 1.1m/min in filtration velocity, and 2.2% at 3.3m/min. These values are much lower than those numerically predicted. It means that the gaseous elemental mercury in a particulate collector was reduced mainly by the activated carbon distributed inside the chamber rather than those collected on the filter surface.