Removal of ammonia using the porous ceramic biofilter inoculated with earthworm casts was characterized. By assuming a plug air flow in the biofilter and applying the Michaelis-Menten equation, the maximum removal rate of $NH_3$ was $280.7g-N{cdot}m^{-3}{cdot}h^{-1}$($18.0g-N{cdot}kg^{-1}{cdot}d^{-1}$) at $30^{circ}C$. $NH_3$ removal rate was increased as temperature increases from $15^{circ}C$ to $35^{circ}C$. The maximum removal rate was $285.8g-N{cdot}m^{-3}{cdot}h^{-1}$($18.8g-N{cdot}kg^{-1}{cdot}d^{-1}$) at $35^{circ}C$. At $15^{circ}C$, the $NH_3$ removal rate was $122.8g-N{cdot}m^{-3}{cdot}h^{-1}$($8.1g-N{cdot}kg^{-1}{cdot}d^{-1}$). When 210 ppm $NH_3$ was supplied to the biofilter at space velocity of $220h^{-1}$, the removal efficiency of $NH_3$ at 15, 25, 30 and $35^{circ}C$ was 80, 90, 95, and 96%, respectively. The removal rate of the ceramic biofilter was 3 to 15 times higher than other biofilters comparing the removal efficiency of $NH_3$ per unit volume of carrier. This result indicates that earthworm casts and porous ceramics are very good inoculum source and carrier, respectively, for the $NH_3$-degrading biofilter.