A denitrification rate measurement using a direct water quality analysis is both laborious and time-consuming and the date may be imprecise especially at a low denitrification rate. Accordingly, the batch respirometric technique that measures the nitrogen gas production rate is evaluated as a reliable, rapid, and simple measurement method. The nitrogen gas production rate can be converted to a dentrification rate by multiplying with a conversion factor, that is the oxidized nitrogen removal equivalent to the nitrogen gas production. The coefficient of variation was 5.7%. The mass of the nitrate-nitrogen removal equivalent to the nitrogen gas production was 1.02 mg/mL. The soluble substance contained in the sample sludge was not found to be a factor affecting the denitrification rate measurement. The carbon dioxide produced during the denitrification reaction was completely converted to bicarbonate dioxide produced during the denitrification reaction was completely converted to bicarbonate ion and did not affect the respirometric denitrification rate data. Based on the results for verification of the respirometric denitrification rate measurement technique, the deitrification rates measured by respirometry and direct water quality analysis were almost the same. These results imply that the respirometric denitrification rate measurement technique, the denitrification rates measured by respirometry and direct water quality analysis were almost the same. These results imply that the respirometric denitrification rate measurement technique can be an effective replacement for the direct water quality analysis method.