PURPOSE: To provide the denitrifying material which decomposes away NOx with high efficiency at a low cost and is effective for both of a moving generating source and a stationary generating source by using a carbon material for removing NOx contg. specific ratios of carbon, oxygen and nitrogen, having a specific combustion temp. in air and further having a specific equilibrium adsorption moisture content.

CONSTITUTION: The element constitution is in the range of 60 to 90wt.% carbon, 5 to 35wt.% oxygen and 2 to 10wt.% nitrogen and is so determined as to have 600 to 800°C combustion temp. (exothermic peak temp. in measurement of temp. rising DTA at 20°C/min) in the air and further 10 to 60% equilibrium adsorption moisture content at 20°C and 100% relative humidity. The carbon material satisfying the requirements that the carbon material is fibrous, the carbon material is curvilinear fibers having a high bulk characteristic, the carbon material is in the form of nonwoven fabric like felt and further the carbon material to be used have 0.02 to 0.20g/cm3 bulk density is more preferable in order to have the excellent contact property with gases and to more efficiently progress the cracking of the gaseous NOx.